{"gene":"CRBN","run_date":"2026-06-09T22:57:19","timeline":{"discoveries":[{"year":2014,"finding":"Crystal structures of DDB1-CRBN bound to thalidomide, lenalidomide, and pomalidomide establish that CRBN is the substrate receptor within the CRL4(CRBN) E3 ubiquitin ligase complex and that it enantioselectively binds IMiDs. IMiDs block endogenous substrates (MEIS2) from binding CRL4(CRBN) while simultaneously recruiting IKZF1/IKZF3 for ubiquitination and degradation. MEIS2 was identified as an endogenous substrate of CRL4(CRBN) by an unbiased screen.","method":"X-ray crystallography (DDB1-CRBN-IMiD co-crystal structures), unbiased substrate screen, ubiquitination assays","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — atomic-resolution crystal structures with functional validation, replicated across multiple IMiD compounds in a single rigorous study","pmids":["25043012"],"is_preprint":false},{"year":2013,"finding":"Lenalidomide and pomalidomide induce interaction of transcription factors Ikaros (IKZF1) and Aiolos (IKZF3) with the CRL4(CRBN) E3 ubiquitin ligase, leading to their enhanced ubiquitination and cereblon-dependent proteasomal degradation in T lymphocytes, thereby relieving transcriptional repression of IL-2 and causing T cell activation.","method":"Co-immunoprecipitation, ubiquitination assays, proteasome inhibitor rescue, CRBN-dependent knockdown experiments, Aiolos degradation confirmed in human subjects administered lenalidomide","journal":"British journal of haematology","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, cell-based ubiquitination assays, in vivo human pharmacodynamic validation, replicated concept across multiple papers","pmids":["24328678"],"is_preprint":false},{"year":2016,"finding":"Crystal structure (2.45 Å) of DDB1-CRBN bound to lenalidomide and CK1α shows that CRBN and lenalidomide jointly provide the binding interface for a CK1α β-hairpin loop in the kinase N-lobe; CK1α binding to CRL4(CRBN) is strictly drug-dependent, and IKZF1 uses a related binding mode, explaining selective lenalidomide efficacy in del(5q) MDS.","method":"X-ray crystallography (ternary complex), in vitro binding assays, mutagenesis","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — atomic-resolution crystal structure of ternary complex with functional mutagenesis validation in a single rigorous study","pmids":["26909574"],"is_preprint":false},{"year":2018,"finding":"Systematic screening of the human C2H2 zinc finger proteome identified 11 zinc finger degrons recruited to the drug-CRBN interface by thalidomide analogs; structural and functional characterization demonstrated that diverse C2H2 zinc finger domains use a shared binding mode at the permissive CRBN surface, and computational docking predicted >150 zinc fingers can bind the drug-CRBN complex in vitro.","method":"Proteome-wide degradation screen, X-ray crystallography of multiple zinc finger-drug-CRBN complexes, biochemical binding assays, computational docking, selective compound modifications","journal":"Science","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures of multiple ternary complexes combined with functional proteomics and mutagenesis in a single comprehensive study","pmids":["30385546"],"is_preprint":false},{"year":2017,"finding":"Pulse-chase SILAC mass spectrometry identified ZFP91 as an IMiD-dependent CRL4(CRBN) neosubstrate; ZFP91 harbors a zinc finger motif related to the IKZF1/3 ZnF that is critical for IMiD-dependent CRBN binding, and lenalidomide induces its ubiquitination and degradation.","method":"pSILAC mass spectrometry, Co-immunoprecipitation, ubiquitination assays, mutagenesis of ZnF motif","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — unbiased proteomics discovery combined with orthogonal biochemical validation and mutagenesis","pmids":["28530236"],"is_preprint":false},{"year":2017,"finding":"p97/VCP is required for degradation of CRL4(CRBN)-ubiquitylated glutamine synthetase (GS) and all four known IMiD-dependent CRBN neosubstrates (IKZF1, IKZF3, CK1α, GSPT1), establishing an intimate functional link between the CRL4(CRBN) E3 ligase and the p97 extraction pathway.","method":"Cell-based ubiquitylation and degradation assays with p97 inhibitors and dominant-negative p97, rescue experiments","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple substrate validation with pharmacological and genetic p97 perturbation, single lab but multiple orthogonal methods","pmids":["28320958"],"is_preprint":false},{"year":2014,"finding":"CRL4A(CRBN) E3 ubiquitin ligase ubiquitinates BK (large conductance Ca2+- and voltage-activated K+) channels and retains them in the endoplasmic reticulum; inactivation of CRL4A(CRBN) releases deubiquitinated BK channels to the plasma membrane, markedly enhancing channel activity and lowering seizure threshold, causing epileptogenesis in mice.","method":"Co-immunoprecipitation, ubiquitination assays, subcellular fractionation/live imaging, electrophysiology, mouse genetic models (brain-specific CRL4A(CRBN) mutation), pharmacological BK channel blockade","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, functional ubiquitination assays, direct localization experiments, in vivo genetic model with defined seizure phenotype rescued by BK channel blockade","pmids":["24845235"],"is_preprint":false},{"year":2018,"finding":"A single I391V amino acid substitution in mouse Crbn (corresponding to human V388) is sufficient to confer sensitivity to thalidomide derivative-induced degradation of Ikaros, Aiolos, Zfp91, and CK1α both in vitro and in vivo, and also recapitulates thalidomide-induced fetal loss in mice.","method":"Mouse knock-in model, in vitro and in vivo degradation assays, genetic epistasis (Trp53 knockout causing lenalidomide resistance)","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Strong — knock-in mouse model with multiple substrate validations in vivo and mechanistic genetic epistasis","pmids":["30064974"],"is_preprint":false},{"year":2018,"finding":"Genome-wide CRISPR-Cas9 screen identified UBE2D3 and UBE2G1 as E2 ubiquitin-conjugating enzymes with distinct roles in CRL4(CRBN)-mediated substrate ubiquitination: UBE2D3 primes targets via monoubiquitination while UBE2G1 extends K48-linked polyubiquitin chains. Loss of UBE2M or COP9 signalosome components alters CUL4A neddylation and impairs lenalidomide-dependent CRL4(CRBN) activity.","method":"Genome-wide CRISPR-Cas9 positive selection screen, IKZF3 degron reporter counterscreen, genetic validation with individual guide RNAs, neddylation assays","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Strong — genome-scale genetic screen with mechanistic follow-up using orthogonal reporter and biochemical assays","pmids":["30042095"],"is_preprint":false},{"year":2020,"finding":"ARID2, a subunit of the PBAF chromatin-remodeling complex, is a pomalidomide-induced neosubstrate of CRL4(CRBN); BRD7 (another PBAF subunit) is required for pomalidomide-induced ARID2 degradation, and ARID2 regulates transcription of pomalidomide target genes including MYC.","method":"Proteomic substrate identification, Co-immunoprecipitation, ubiquitination assays, CRBN-dependent degradation rescue experiments, transcriptional reporter assays","journal":"Nature chemical biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — proteomics-based substrate discovery with multiple orthogonal validations including Co-IP, ubiquitination, and transcriptional readouts","pmids":["32958952"],"is_preprint":false},{"year":2021,"finding":"CRBN functions as a co-chaperone that specifically determines HSP90 chaperone activity toward transmembrane proteins by counteracting AHA1; IMiDs disrupt the CRBN-HSP90 interaction, impairing transmembrane protein quality control. LAT1/CD98hc was identified as a client of the CRBN-AHA1-HSP90 axis and a determinant of IMiD activity in multiple myeloma.","method":"Co-immunoprecipitation, cell surface proteomics, genetic knockdown/knockout experiments, functional assays in MM cells","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP establishing the CRBN-HSP90-AHA1 complex, combined with proteomics and functional validation in multiple cell systems","pmids":["33571422"],"is_preprint":false},{"year":2021,"finding":"USP15 deubiquitylase antagonizes CRL4(CRBN)-mediated ubiquitylation of the natural substrate glutamine synthetase (GS) and neosubstrates IKZF1, IKZF3, CK1α, RNF166, GSPT1, and BRD4, thereby preventing their degradation; USP15 is highly expressed in IMiD-resistant cells and its depletion sensitizes cells to lenalidomide.","method":"Ubiquitylation assays, protein stability assays, USP15 knockdown/overexpression, IMiD resistance cell models","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple substrate validation with genetic perturbation, single lab","pmids":["34583995"],"is_preprint":false},{"year":2021,"finding":"PLZF/ZBTB16 and its leukemogenic fusion proteins (e.g., PLZF-RARα) are pomalidomide-dependent neosubstrates of CRL4(CRBN); pomalidomide treatment induces their ubiquitination and degradation via CRBN, leading to antiproliferation of leukemic cells expressing PLZF-RARα.","method":"Co-immunoprecipitation, ubiquitination assays, CRBN-dependent degradation rescue, cell proliferation assays","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP and ubiquitination with functional cell-based readout, single lab","pmids":["34764413"],"is_preprint":false},{"year":2020,"finding":"KPNB1 (Karyopherin β1) is required for nuclear import of CRBN; CRBN nuclear localization is necessary for pomalidomide-dependent degradation of the nuclear transcription factor Aiolos, whereas the cytoplasmic translation factor GSPT1 is degraded by CC-885 only when CRBN is present in the cytoplasm, demonstrating that subcellular distribution of CRBN is critical for drug efficacy.","method":"Genome-wide shRNA screen, genetic knockdown of KPNB1, subcellular fractionation, nuclear import assays, substrate degradation assays","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genome-wide screen plus targeted validation of CRBN localization and substrate degradation, single lab","pmids":["32132601"],"is_preprint":false},{"year":2014,"finding":"CRBN negatively regulates AMPK activity in vivo and in vitro, and thereby activates mTOR-dependent protein synthesis; CRBN-deficient mice show repressed protein translation via the AMPK-mTOR cascade. A pathogenic C-terminal 24-amino acid deletion mutant (found in human patients with mild mental retardation) fails to rescue mTOR-dependent translational repression in CRBN-deficient fibroblasts.","method":"CRBN knockout mice, ectopic expression of wild-type vs. mutant CRBN, AMPK activity assays, mTOR signaling readouts, protein synthesis measurements","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo KO model with in vitro mutagenesis validation, single lab, multiple readouts","pmids":["24993823"],"is_preprint":false},{"year":2021,"finding":"CRBN inhibits TRAF6-induced ubiquitination of ECSIT (blocking mitochondrial ROS production needed for bactericidal activity) and ubiquitination of BECN1 (Beclin 1), thereby suppressing autophagy; CRBN mitochondrial localization is increased upon TLR4 stimulation, and CRBN knockdown/knockout enhances autophagy and bactericidal activity against S. typhimurium.","method":"Co-immunoprecipitation, ubiquitination assays, CRBN knockdown/knockout cell models, mitochondrial localization by fractionation, mROS measurement, bacterial infection assays","journal":"Frontiers in immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP and ubiquitination assays with functional readouts and subcellular localization data, single lab","pmids":["31620128"],"is_preprint":false},{"year":2021,"finding":"Thalidomide does not affect AMPK activation or CRBN-AMPK α subunit binding affinity, indicating that CRBN's negative regulation of AMPK operates through a mechanism independent of the IMiD-binding region. The N-terminal region and C-terminal tail of CRBN (distinct from the IMiD binding site) are required for interaction with the AMPK α subunit.","method":"AMPK activity assays with/without thalidomide, binding affinity measurements, domain-deletion/mutagenesis analysis of CRBN","journal":"Pharmaceuticals","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — domain mutagenesis with functional AMPK assays, single lab, defines distinct CRBN interaction regions","pmids":["34073624"],"is_preprint":false},{"year":2020,"finding":"The CUL4-DDB1-CRBN E3 ubiquitin ligase promotes polyubiquitination and proteasomal degradation of ClC-2 chloride channels; CRBN co-exists in the same complex with ClC-2 and promotes its degradation. The CRBN-targeting drug lenalidomide promotes ClC-2 degradation, while the cullin inhibitor MLN4924 attenuates it. Disease-associated ClC-2 mutants causing aldosteronism or leukodystrophy show opposite alterations in CUL4-mediated proteostasis.","method":"Co-immunoprecipitation, ubiquitination assays, pharmacological modulation (lenalidomide, MLN4924), heterologous expression and native cell studies, functional electrophysiology","journal":"Cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP establishing CRBN-ClC-2 complex, multiple orthogonal methods, single lab","pmids":["32466489"],"is_preprint":false},{"year":2025,"finding":"PCMT1 (protein carboxymethyltransferase) promotes formation of C-terminal cyclic imide modifications on C-terminal asparagine residues of CRBN substrates (including glutamine synthetase/GLUL and inorganic pyrophosphatase 1/PPA1), thereby generating the degron recognized by CRBN. PCMT1 and CRBN co-regulate the levels of these metabolic enzymes in vitro, in cells, and in vivo, and this regulation is associated with the proepileptic phenotype of CRBN knockout mice.","method":"In vitro enzymatic assays, cell-based protein stability experiments, in vivo mouse models (CRBN KO), chemical biology tools, co-regulation analysis","journal":"Nature chemical biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution of PCMT1-catalyzed degron formation, validated in cells and in vivo, multiple orthogonal methods in peer-reviewed publication","pmids":["41461925"],"is_preprint":false},{"year":2025,"finding":"PCMT1 promotes formation of the C-terminal cyclic imide degron on CRBN substrates glutamine synthetase (GLUL) and PPA1 (preprint version of the same discovery); PCMT1 and CRBN co-regulate these metabolic enzymes in vitro, in cells, and in vivo.","method":"In vitro enzymatic assays, cell-based protein stability assays, mouse models","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with in vivo validation, preprint not yet peer-reviewed; superseded/confirmed by PMID 41461925","pmids":["40196534"],"is_preprint":true},{"year":2020,"finding":"Thalidomide-induced degradation of SALL4 via CRBN is responsible for disruption of human iPSC mesendoderm/lateral plate mesoderm differentiation; CRBN V388I mutation or SALL4 G416A mutation abrogates both SALL4 degradation and the teratogenic effects on LPM differentiation, establishing a CRBN-SALL4 axis in thalidomide teratogenicity.","method":"Engineered hiPSC lines with CRBN or SALL4 point mutations, differentiation assays, SALL4 protein stability assays","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean genetic rescue experiments with two independent mutations (CRBN and SALL4) in physiologically relevant human pluripotent stem cell model, multiple orthogonal methods","pmids":["32071327"],"is_preprint":false},{"year":2020,"finding":"CC-885 (a cereblon modulator) selectively promotes CRBN- and p97-dependent PLK1 ubiquitination and proteasomal degradation in non-small cell lung cancer cells, identifying PLK1 as a neosubstrate of CUL4-CRBN induced by CC-885.","method":"Ubiquitination assays, CRBN and p97 genetic depletion (rescue experiments), protein degradation assays, in vitro and in vivo tumor models","journal":"Molecular therapy oncolytics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic validation with CRBN/p97 knockdown and ubiquitination assays, single lab","pmids":["32728610"],"is_preprint":false},{"year":2021,"finding":"CC-885 selectively induces CRBN-dependent ubiquitination and proteasomal degradation of CDK4 in multiple myeloma cells; CDK4 destruction by CC-885 decreases RB phosphorylation and suppresses E2F downstream gene expression.","method":"Ubiquitination assays, CRBN genetic ablation (rescue), protein degradation assays, RB phosphorylation readouts, cell cycle analysis","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRBN-dependent ubiquitination established by genetic rescue, single lab","pmids":["33676183"],"is_preprint":false},{"year":2025,"finding":"A molecular glue degrader (MRT-31619) drives homo-dimerization of CRBN via two molecules assembling into a helix-like structure that mimics a neosubstrate G-loop degron, promoting CRBN self-ubiquitination and fast, potent, selective degradation by the ubiquitin-proteasome system. Cryo-EM structure of the CRBN homodimer reveals this unique mechanism.","method":"Cryo-EM structure determination, cellular degradation assays, quantitative proteomics, chemical biology","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cryo-EM structure of the homo-dimerization complex with functional degradation validation, single lab but orthogonal structural and biochemical methods","pmids":["41258141"],"is_preprint":false},{"year":2023,"finding":"CRBN interacts with and mediates AZD7762-dependent ubiquitination of BAG3; AZD7762-induced BAG3 degradation is CRBN-dependent and occurs through the ubiquitin-proteasome pathway, independent of Chk1 expression or activity.","method":"Co-immunoprecipitation, ubiquitination assays, CRBN-dependent rescue experiments, western blot, cell viability assays","journal":"Anti-cancer drugs","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP and ubiquitination assay, single lab, limited mechanistic follow-up","pmids":["37449977"],"is_preprint":false},{"year":2025,"finding":"MORF4L1 (a chromatin-remodeling MRG family protein) is identified as an endogenous CRBN substrate; CRBN promotes MORF4L1 ubiquitination and degradation under physiological conditions, further enhanced by CC-885, as shown by Co-IP and structural modeling.","method":"Proteomic analysis, co-immunoprecipitation, structural modeling, protein stability assays","journal":"Scientific reports","confidence":"Low","confidence_rationale":"Tier 3 / Weak — Co-IP and proteomics without full biochemical reconstitution, single lab, structural modeling is computational","pmids":["39827217"],"is_preprint":false},{"year":2025,"finding":"USP2 directly interacts with CRBN and promotes its deubiquitination and stabilization in senescent liver cancer cells, making them sensitive to CRBN-based PROTAC therapy.","method":"Co-immunoprecipitation, deubiquitination assays, genetic USP2 depletion, protein stability measurements","journal":"Gastroenterology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP showing USP2-CRBN interaction with functional CRBN stability readout, single lab","pmids":["38262581"],"is_preprint":false},{"year":2019,"finding":"Crystal structures of hydrolyzed thalidomide metabolites bound to the CRBN thalidomide-binding domain reveal binding mode of minimalistic CRBN effectors; a de-novo CRBN effector was designed from this scaffold that degrades the neosubstrate IKZF3 in cells.","method":"X-ray crystallography of CRBN-ligand complexes, cell-based IKZF3 degradation assays","journal":"Journal of medicinal chemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — crystal structures informing binding mode with cell-based functional validation, single lab","pmids":["31251063"],"is_preprint":false},{"year":2025,"finding":"A crystal structure of the DDB1/CRBN/lenalidomide complex with greater resolution than previously published was generated; dynamic modeling using this structure helped explain the differential impact of CRBN missense mutations on IMiD and CELMoD agent activity, including identification of mutations that can be overcome by more potent CELMoDs.","method":"X-ray crystallography (DDB1-CRBN-lenalidomide complex), structure-guided dynamic modeling, functional cell-based degradation assays, confirmatory mutagenesis experiments","journal":"Blood","confidence":"High","confidence_rationale":"Tier 1 / Moderate — high-resolution crystal structure with functional mutant validation, single lab, multiple orthogonal methods","pmids":["39841463"],"is_preprint":false}],"current_model":"CRBN is the substrate receptor of the CUL4-RBX1-DDB1-CRBN (CRL4CRBN) E3 ubiquitin ligase complex; it enantioselectively binds thalidomide and its IMiD derivatives at a defined pocket (established by crystal structures), and this binding reprograms the ligase to recruit and ubiquitinate a diverse set of neosubstrates—including IKZF1/3, CK1α, ZFP91, SALL4, ARID2, PLZF, and C2H2 zinc finger proteins—through a shared interface between the drug and a degron (often a G-loop or β-hairpin) on the neosubstrate; endogenous substrates (e.g., glutamine synthetase, MEIS2, ClC-2, BK channels) are recognized via a C-terminal cyclic imide degron generated by PCMT1; downstream, ubiquitylated substrates require p97/VCP for extraction and the E2 enzymes UBE2D3 (monoubiquitination priming) and UBE2G1 (K48 chain elongation) for efficient proteasomal degradation; USP15 antagonizes this degradation; CRBN additionally functions as a co-chaperone counteracting AHA1 to regulate HSP90 activity toward transmembrane protein clients, negatively regulates AMPK (via its N-terminal/C-terminal tail independent of the IMiD-binding site) to promote mTOR-dependent protein synthesis, inhibits TRAF6-dependent ubiquitination of ECSIT and Beclin-1, and controls BK channel ER retention—all constituting functions distinct from IMiD-induced neosubstrate degradation."},"narrative":{"mechanistic_narrative":"CRBN is the substrate-recognition receptor of the CUL4-RBX1-DDB1-CRBN (CRL4CRBN) E3 ubiquitin ligase, where it dictates which proteins are ubiquitinated for proteasomal destruction [PMID:25043012]. CRBN possesses a defined pocket that enantioselectively binds thalidomide and immunomodulatory imide drugs (IMiDs); drug occupancy creates a composite drug-CRBN surface that simultaneously blocks endogenous substrate binding (e.g., MEIS2) and reprograms the ligase to recruit neosubstrates [PMID:25043012]. Crystal structures show that this neosubstrate interface engages a shared structural degron — a β-hairpin/G-loop presented by the kinase N-lobe of CK1α or the zinc-finger domains of IKZF1/IKZF3 [PMID:24328678, PMID:26909574] — and proteome-wide screening established that diverse C2H2 zinc-finger proteins, including ZFP91, dock at this permissive surface through a common mode [PMID:30385546, PMID:28530236]. The same drug-dependent recruitment extends to SALL4, ARID2, PLZF/ZBTB16 and additional targets accessed by cereblon modulators [PMID:32958952, PMID:34764413, PMID:32071327]. Endogenous, drug-independent substrates are recognized through a distinct C-terminal cyclic imide degron installed on asparagine residues by PCMT1, which co-regulates metabolic enzymes such as glutamine synthetase with CRBN [PMID:41461925]. Productive degradation of CRL4CRBN-ubiquitinated substrates requires the E2 enzymes UBE2D3 (monoubiquitin priming) and UBE2G1 (K48 chain elongation), CUL4 neddylation, and p97/VCP-mediated extraction, while USP15 deubiquitinates substrates to antagonize their turnover [PMID:28320958, PMID:30042095, PMID:34583995]. Beyond its ligase function, CRBN ubiquitinates and controls trafficking of ion channels: it retains BK channels in the ER, with loss of CRL4A(CRBN) activity lowering seizure threshold in mice, and it promotes degradation of ClC-2 chloride channels [PMID:24845235, PMID:32466489]. CRBN also acts as an HSP90 co-chaperone that counteracts AHA1 for transmembrane-client quality control [PMID:33571422], and negatively regulates AMPK through its N- and C-terminal regions independently of the IMiD pocket to sustain mTOR-dependent translation [PMID:24993823, PMID:34073624]. A C-terminal truncation mutant that fails to support mTOR-dependent translation is linked to human mild mental retardation [PMID:24993823].","teleology":[{"year":2013,"claim":"Established the first molecular consequence of CRBN engagement by IMiDs — that lenalidomide/pomalidomide redirect CRL4CRBN to destroy specific transcription factors — answering how these drugs exert immunomodulatory effects.","evidence":"Co-IP, ubiquitination assays, proteasome rescue, and in vivo human pharmacodynamic detection of Aiolos loss","pmids":["24328678"],"confidence":"High","gaps":["Did not provide the structural basis of drug-induced recruitment","Endogenous substrate repertoire unaddressed"]},{"year":2014,"claim":"Defined CRBN as the substrate receptor of CRL4CRBN and showed atomically that IMiD binding both blocks an endogenous substrate (MEIS2) and recruits neosubstrates (IKZF1/3), unifying drug binding and substrate reprogramming.","evidence":"X-ray crystallography of DDB1-CRBN-IMiD complexes plus unbiased substrate screen and ubiquitination assays","pmids":["25043012"],"confidence":"High","gaps":["Did not resolve a ternary drug-CRBN-neosubstrate structure","Scope of neosubstrate degron not generalized"]},{"year":2014,"claim":"Revealed CRBN ligase functions beyond IMiD biology — ubiquitination and ER retention of BK channels, and a drug-independent AMPK-mTOR translational role with a disease-linked truncation mutant.","evidence":"Mouse genetic models, electrophysiology, AMPK/mTOR readouts, and rescue with WT vs. patient mutant CRBN","pmids":["24845235","24993823"],"confidence":"High","gaps":["AMPK regulation mechanism (which domain, direct vs. indirect) not defined at this stage","BK degron not characterized"]},{"year":2016,"claim":"Solved the ternary CRBN-lenalidomide-CK1α structure, showing CRBN and the drug jointly form the neosubstrate interface engaging a β-hairpin degron, explaining selective del(5q) MDS efficacy.","evidence":"2.45 Å ternary crystal structure with in vitro binding and mutagenesis","pmids":["26909574"],"confidence":"High","gaps":["Generality of the degron mode across other substrate classes untested here"]},{"year":2017,"claim":"Generalized the neosubstrate concept by identifying ZFP91 via unbiased proteomics and linking it to an IKZF-related zinc-finger degron, and established that p97/VCP extraction is required downstream of ubiquitination.","evidence":"pSILAC mass spectrometry, ZnF mutagenesis, and p97 inhibition/dominant-negative rescue across multiple substrates","pmids":["28530236","28320958"],"confidence":"High","gaps":["E2 enzyme identities not yet defined","Mechanism of p97 substrate handoff unresolved"]},{"year":2018,"claim":"Systematized the degron rules by mapping the C2H2 zinc-finger degron space and defined the enzymatic machinery (UBE2D3 priming, UBE2G1 elongation, neddylation control) plus an in vivo CRBN residue (I391V/V388) sufficient to confer drug sensitivity and teratogenicity.","evidence":"Proteome-wide degradation screen with multiple ternary crystal structures; genome-wide CRISPR screen; knock-in mouse model","pmids":["30385546","30042095","30064974"],"confidence":"High","gaps":["Endogenous physiological degron chemistry still unknown","How E2 selection is achieved mechanistically unresolved"]},{"year":2020,"claim":"Broadened the substrate landscape (SALL4, ARID2, PLK1, CDK4) and showed subcellular distribution of CRBN, via KPNB1-mediated nuclear import, governs which substrates can be degraded; linked SALL4 degradation directly to thalidomide teratogenicity.","evidence":"Engineered hiPSC point-mutant rescue, proteomics/Co-IP, KPNB1 knockdown with fractionation and degradation assays","pmids":["32071327","32958952","32132601","32728610"],"confidence":"High","gaps":["Most neosubstrates validated in single-lab cell systems","Endogenous functions of these substrates under CRBN control incompletely mapped"]},{"year":2021,"claim":"Defined antagonists and non-ligase functions: USP15 reverses CRL4CRBN ubiquitination of substrates; CRBN acts as an HSP90 co-chaperone counteracting AHA1; and AMPK regulation was shown to operate independently of the IMiD pocket via N-/C-terminal regions.","evidence":"Deubiquitination/stability assays, reciprocal Co-IP and cell-surface proteomics, and domain-deletion AMPK binding/activity assays","pmids":["34583995","33571422","34073624","31620128"],"confidence":"Medium","gaps":["Non-ligase functions largely single-lab","Structural basis of CRBN-HSP90 and CRBN-AMPK interactions undefined"]},{"year":2025,"claim":"Identified the endogenous degron chemistry — PCMT1 generates C-terminal cyclic imide degrons that CRBN recognizes — and demonstrated a homo-dimerization molecular-glue mechanism inducing CRBN self-degradation, plus high-resolution structures rationalizing clinical CRBN mutations.","evidence":"In vitro enzymatic reconstitution with cellular/in vivo validation (PCMT1); cryo-EM of CRBN homodimer; high-resolution DDB1-CRBN-lenalidomide crystallography with dynamic modeling","pmids":["41461925","41258141","39841463"],"confidence":"High","gaps":["Full endogenous substrate repertoire defined by cyclic imide degron incomplete","Physiological role of CRBN self-degradation unclear"]},{"year":null,"claim":"How CRBN's diverse non-ligase activities (HSP90 co-chaperone, AMPK regulation, mitochondrial/autophagy control) are integrated with its CRL4 receptor function, and the full physiological substrate set defined by the PCMT1 cyclic imide degron, remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified structural/cellular model linking ligase and non-ligase roles","Endogenous substrate landscape not comprehensively mapped","Several low-confidence substrate/regulator findings (BAG3, MORF4L1, USP2) await independent validation"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1,6,17]},{"term_id":"GO:0016874","term_label":"ligase activity","supporting_discovery_ids":[0,5,8]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,2,3]},{"term_id":"GO:0044183","term_label":"protein folding chaperone","supporting_discovery_ids":[10]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[14,16]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[13]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[13]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[6,17]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[15]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,1,5,8]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[6,14,20]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[14,16]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[15]}],"complexes":["CRL4CRBN (CUL4-RBX1-DDB1-CRBN E3 ubiquitin ligase)","CRBN-AHA1-HSP90 chaperone axis"],"partners":["DDB1","CUL4A","UBE2G1","UBE2D3","USP15","HSP90","AHA1","KPNB1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q96SW2","full_name":"Protein cereblon","aliases":[],"length_aa":442,"mass_kda":50.5,"function":"Substrate recognition component of a DCX (DDB1-CUL4-X-box) E3 protein ligase complex that mediates the ubiquitination and subsequent proteasomal degradation of target proteins, such as MEIS2, ILF2 or GLUL (PubMed:26990986, PubMed:33009960). Normal degradation of key regulatory proteins is required for normal limb outgrowth and expression of the fibroblast growth factor FGF8 (PubMed:20223979, PubMed:24328678, PubMed:25043012, PubMed:25108355). Maintains presynaptic glutamate release and consequently cognitive functions, such as memory and learning, by negatively regulating large-conductance calcium-activated potassium (BK) channels in excitatory neurons (PubMed:18414909, PubMed:29530986). Likely to function by regulating the assembly and neuronal surface expression of BK channels via its interaction with KCNT1 (PubMed:18414909). May also be involved in regulating anxiety-like behaviors via a BK channel-independent mechanism (By similarity). Plays a negative role in TLR4 signaling by interacting with TRAF6 and ECSIT, leading to inhibition of ECSIT ubiquitination, an important step of the signaling (PubMed:31620128)","subcellular_location":"Cytoplasm; Nucleus; Membrane","url":"https://www.uniprot.org/uniprotkb/Q96SW2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CRBN","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"DDB1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/CRBN","total_profiled":1310},"omim":[{"mim_id":"609262","title":"CEREBLON; CRBN","url":"https://www.omim.org/entry/609262"},{"mim_id":"607417","title":"INTELLECTUAL DEVELOPMENTAL DISORDER, AUTOSOMAL RECESSIVE 2; MRT2","url":"https://www.omim.org/entry/607417"},{"mim_id":"606221","title":"IKAROS FAMILY ZINC FINGER 3; IKZF3","url":"https://www.omim.org/entry/606221"},{"mim_id":"603137","title":"CULLIN 4A; CUL4A","url":"https://www.omim.org/entry/603137"},{"mim_id":"603023","title":"IKAROS FAMILY ZINC FINGER 1; IKZF1","url":"https://www.omim.org/entry/603023"}],"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/CRBN"},"hgnc":{"alias_symbol":["MRT2"],"prev_symbol":["MRT2A"]},"alphafold":{"accession":"Q96SW2","domains":[{"cath_id":"2.170.150.20","chopping":"38-56_325-424","consensus_level":"high","plddt":93.0122,"start":38,"end":424},{"cath_id":"2.30.130.40","chopping":"76-183","consensus_level":"high","plddt":93.8428,"start":76,"end":183},{"cath_id":"1.20.58.1480","chopping":"190-206_241-317","consensus_level":"medium","plddt":92.6498,"start":190,"end":317}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96SW2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96SW2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96SW2-F1-predicted_aligned_error_v6.png","plddt_mean":86.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CRBN","jax_strain_url":"https://www.jax.org/strain/search?query=CRBN"},"sequence":{"accession":"Q96SW2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96SW2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96SW2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96SW2"}},"corpus_meta":[{"pmid":"25043012","id":"PMC_25043012","title":"Structure 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lenalidomide, and pomalidomide establish that CRBN is the substrate receptor within the CRL4(CRBN) E3 ubiquitin ligase complex and that it enantioselectively binds IMiDs. IMiDs block endogenous substrates (MEIS2) from binding CRL4(CRBN) while simultaneously recruiting IKZF1/IKZF3 for ubiquitination and degradation. MEIS2 was identified as an endogenous substrate of CRL4(CRBN) by an unbiased screen.\",\n      \"method\": \"X-ray crystallography (DDB1-CRBN-IMiD co-crystal structures), unbiased substrate screen, ubiquitination assays\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — atomic-resolution crystal structures with functional validation, replicated across multiple IMiD compounds in a single rigorous study\",\n      \"pmids\": [\"25043012\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Lenalidomide and pomalidomide induce interaction of transcription factors Ikaros (IKZF1) and Aiolos (IKZF3) with the CRL4(CRBN) E3 ubiquitin ligase, leading to their enhanced ubiquitination and cereblon-dependent proteasomal degradation in T lymphocytes, thereby relieving transcriptional repression of IL-2 and causing T cell activation.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, proteasome inhibitor rescue, CRBN-dependent knockdown experiments, Aiolos degradation confirmed in human subjects administered lenalidomide\",\n      \"journal\": \"British journal of haematology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, cell-based ubiquitination assays, in vivo human pharmacodynamic validation, replicated concept across multiple papers\",\n      \"pmids\": [\"24328678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Crystal structure (2.45 Å) of DDB1-CRBN bound to lenalidomide and CK1α shows that CRBN and lenalidomide jointly provide the binding interface for a CK1α β-hairpin loop in the kinase N-lobe; CK1α binding to CRL4(CRBN) is strictly drug-dependent, and IKZF1 uses a related binding mode, explaining selective lenalidomide efficacy in del(5q) MDS.\",\n      \"method\": \"X-ray crystallography (ternary complex), in vitro binding assays, mutagenesis\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — atomic-resolution crystal structure of ternary complex with functional mutagenesis validation in a single rigorous study\",\n      \"pmids\": [\"26909574\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Systematic screening of the human C2H2 zinc finger proteome identified 11 zinc finger degrons recruited to the drug-CRBN interface by thalidomide analogs; structural and functional characterization demonstrated that diverse C2H2 zinc finger domains use a shared binding mode at the permissive CRBN surface, and computational docking predicted >150 zinc fingers can bind the drug-CRBN complex in vitro.\",\n      \"method\": \"Proteome-wide degradation screen, X-ray crystallography of multiple zinc finger-drug-CRBN complexes, biochemical binding assays, computational docking, selective compound modifications\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures of multiple ternary complexes combined with functional proteomics and mutagenesis in a single comprehensive study\",\n      \"pmids\": [\"30385546\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Pulse-chase SILAC mass spectrometry identified ZFP91 as an IMiD-dependent CRL4(CRBN) neosubstrate; ZFP91 harbors a zinc finger motif related to the IKZF1/3 ZnF that is critical for IMiD-dependent CRBN binding, and lenalidomide induces its ubiquitination and degradation.\",\n      \"method\": \"pSILAC mass spectrometry, Co-immunoprecipitation, ubiquitination assays, mutagenesis of ZnF motif\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — unbiased proteomics discovery combined with orthogonal biochemical validation and mutagenesis\",\n      \"pmids\": [\"28530236\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"p97/VCP is required for degradation of CRL4(CRBN)-ubiquitylated glutamine synthetase (GS) and all four known IMiD-dependent CRBN neosubstrates (IKZF1, IKZF3, CK1α, GSPT1), establishing an intimate functional link between the CRL4(CRBN) E3 ligase and the p97 extraction pathway.\",\n      \"method\": \"Cell-based ubiquitylation and degradation assays with p97 inhibitors and dominant-negative p97, rescue experiments\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple substrate validation with pharmacological and genetic p97 perturbation, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"28320958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"CRL4A(CRBN) E3 ubiquitin ligase ubiquitinates BK (large conductance Ca2+- and voltage-activated K+) channels and retains them in the endoplasmic reticulum; inactivation of CRL4A(CRBN) releases deubiquitinated BK channels to the plasma membrane, markedly enhancing channel activity and lowering seizure threshold, causing epileptogenesis in mice.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, subcellular fractionation/live imaging, electrophysiology, mouse genetic models (brain-specific CRL4A(CRBN) mutation), pharmacological BK channel blockade\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, functional ubiquitination assays, direct localization experiments, in vivo genetic model with defined seizure phenotype rescued by BK channel blockade\",\n      \"pmids\": [\"24845235\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"A single I391V amino acid substitution in mouse Crbn (corresponding to human V388) is sufficient to confer sensitivity to thalidomide derivative-induced degradation of Ikaros, Aiolos, Zfp91, and CK1α both in vitro and in vivo, and also recapitulates thalidomide-induced fetal loss in mice.\",\n      \"method\": \"Mouse knock-in model, in vitro and in vivo degradation assays, genetic epistasis (Trp53 knockout causing lenalidomide resistance)\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — knock-in mouse model with multiple substrate validations in vivo and mechanistic genetic epistasis\",\n      \"pmids\": [\"30064974\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Genome-wide CRISPR-Cas9 screen identified UBE2D3 and UBE2G1 as E2 ubiquitin-conjugating enzymes with distinct roles in CRL4(CRBN)-mediated substrate ubiquitination: UBE2D3 primes targets via monoubiquitination while UBE2G1 extends K48-linked polyubiquitin chains. Loss of UBE2M or COP9 signalosome components alters CUL4A neddylation and impairs lenalidomide-dependent CRL4(CRBN) activity.\",\n      \"method\": \"Genome-wide CRISPR-Cas9 positive selection screen, IKZF3 degron reporter counterscreen, genetic validation with individual guide RNAs, neddylation assays\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genome-scale genetic screen with mechanistic follow-up using orthogonal reporter and biochemical assays\",\n      \"pmids\": [\"30042095\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ARID2, a subunit of the PBAF chromatin-remodeling complex, is a pomalidomide-induced neosubstrate of CRL4(CRBN); BRD7 (another PBAF subunit) is required for pomalidomide-induced ARID2 degradation, and ARID2 regulates transcription of pomalidomide target genes including MYC.\",\n      \"method\": \"Proteomic substrate identification, Co-immunoprecipitation, ubiquitination assays, CRBN-dependent degradation rescue experiments, transcriptional reporter assays\",\n      \"journal\": \"Nature chemical biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — proteomics-based substrate discovery with multiple orthogonal validations including Co-IP, ubiquitination, and transcriptional readouts\",\n      \"pmids\": [\"32958952\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CRBN functions as a co-chaperone that specifically determines HSP90 chaperone activity toward transmembrane proteins by counteracting AHA1; IMiDs disrupt the CRBN-HSP90 interaction, impairing transmembrane protein quality control. LAT1/CD98hc was identified as a client of the CRBN-AHA1-HSP90 axis and a determinant of IMiD activity in multiple myeloma.\",\n      \"method\": \"Co-immunoprecipitation, cell surface proteomics, genetic knockdown/knockout experiments, functional assays in MM cells\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP establishing the CRBN-HSP90-AHA1 complex, combined with proteomics and functional validation in multiple cell systems\",\n      \"pmids\": [\"33571422\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"USP15 deubiquitylase antagonizes CRL4(CRBN)-mediated ubiquitylation of the natural substrate glutamine synthetase (GS) and neosubstrates IKZF1, IKZF3, CK1α, RNF166, GSPT1, and BRD4, thereby preventing their degradation; USP15 is highly expressed in IMiD-resistant cells and its depletion sensitizes cells to lenalidomide.\",\n      \"method\": \"Ubiquitylation assays, protein stability assays, USP15 knockdown/overexpression, IMiD resistance cell models\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple substrate validation with genetic perturbation, single lab\",\n      \"pmids\": [\"34583995\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"PLZF/ZBTB16 and its leukemogenic fusion proteins (e.g., PLZF-RARα) are pomalidomide-dependent neosubstrates of CRL4(CRBN); pomalidomide treatment induces their ubiquitination and degradation via CRBN, leading to antiproliferation of leukemic cells expressing PLZF-RARα.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, CRBN-dependent degradation rescue, cell proliferation assays\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP and ubiquitination with functional cell-based readout, single lab\",\n      \"pmids\": [\"34764413\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"KPNB1 (Karyopherin β1) is required for nuclear import of CRBN; CRBN nuclear localization is necessary for pomalidomide-dependent degradation of the nuclear transcription factor Aiolos, whereas the cytoplasmic translation factor GSPT1 is degraded by CC-885 only when CRBN is present in the cytoplasm, demonstrating that subcellular distribution of CRBN is critical for drug efficacy.\",\n      \"method\": \"Genome-wide shRNA screen, genetic knockdown of KPNB1, subcellular fractionation, nuclear import assays, substrate degradation assays\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genome-wide screen plus targeted validation of CRBN localization and substrate degradation, single lab\",\n      \"pmids\": [\"32132601\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"CRBN negatively regulates AMPK activity in vivo and in vitro, and thereby activates mTOR-dependent protein synthesis; CRBN-deficient mice show repressed protein translation via the AMPK-mTOR cascade. A pathogenic C-terminal 24-amino acid deletion mutant (found in human patients with mild mental retardation) fails to rescue mTOR-dependent translational repression in CRBN-deficient fibroblasts.\",\n      \"method\": \"CRBN knockout mice, ectopic expression of wild-type vs. mutant CRBN, AMPK activity assays, mTOR signaling readouts, protein synthesis measurements\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo KO model with in vitro mutagenesis validation, single lab, multiple readouts\",\n      \"pmids\": [\"24993823\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CRBN inhibits TRAF6-induced ubiquitination of ECSIT (blocking mitochondrial ROS production needed for bactericidal activity) and ubiquitination of BECN1 (Beclin 1), thereby suppressing autophagy; CRBN mitochondrial localization is increased upon TLR4 stimulation, and CRBN knockdown/knockout enhances autophagy and bactericidal activity against S. typhimurium.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, CRBN knockdown/knockout cell models, mitochondrial localization by fractionation, mROS measurement, bacterial infection assays\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP and ubiquitination assays with functional readouts and subcellular localization data, single lab\",\n      \"pmids\": [\"31620128\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Thalidomide does not affect AMPK activation or CRBN-AMPK α subunit binding affinity, indicating that CRBN's negative regulation of AMPK operates through a mechanism independent of the IMiD-binding region. The N-terminal region and C-terminal tail of CRBN (distinct from the IMiD binding site) are required for interaction with the AMPK α subunit.\",\n      \"method\": \"AMPK activity assays with/without thalidomide, binding affinity measurements, domain-deletion/mutagenesis analysis of CRBN\",\n      \"journal\": \"Pharmaceuticals\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain mutagenesis with functional AMPK assays, single lab, defines distinct CRBN interaction regions\",\n      \"pmids\": [\"34073624\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"The CUL4-DDB1-CRBN E3 ubiquitin ligase promotes polyubiquitination and proteasomal degradation of ClC-2 chloride channels; CRBN co-exists in the same complex with ClC-2 and promotes its degradation. The CRBN-targeting drug lenalidomide promotes ClC-2 degradation, while the cullin inhibitor MLN4924 attenuates it. Disease-associated ClC-2 mutants causing aldosteronism or leukodystrophy show opposite alterations in CUL4-mediated proteostasis.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, pharmacological modulation (lenalidomide, MLN4924), heterologous expression and native cell studies, functional electrophysiology\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP establishing CRBN-ClC-2 complex, multiple orthogonal methods, single lab\",\n      \"pmids\": [\"32466489\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PCMT1 (protein carboxymethyltransferase) promotes formation of C-terminal cyclic imide modifications on C-terminal asparagine residues of CRBN substrates (including glutamine synthetase/GLUL and inorganic pyrophosphatase 1/PPA1), thereby generating the degron recognized by CRBN. PCMT1 and CRBN co-regulate the levels of these metabolic enzymes in vitro, in cells, and in vivo, and this regulation is associated with the proepileptic phenotype of CRBN knockout mice.\",\n      \"method\": \"In vitro enzymatic assays, cell-based protein stability experiments, in vivo mouse models (CRBN KO), chemical biology tools, co-regulation analysis\",\n      \"journal\": \"Nature chemical biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution of PCMT1-catalyzed degron formation, validated in cells and in vivo, multiple orthogonal methods in peer-reviewed publication\",\n      \"pmids\": [\"41461925\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PCMT1 promotes formation of the C-terminal cyclic imide degron on CRBN substrates glutamine synthetase (GLUL) and PPA1 (preprint version of the same discovery); PCMT1 and CRBN co-regulate these metabolic enzymes in vitro, in cells, and in vivo.\",\n      \"method\": \"In vitro enzymatic assays, cell-based protein stability assays, mouse models\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with in vivo validation, preprint not yet peer-reviewed; superseded/confirmed by PMID 41461925\",\n      \"pmids\": [\"40196534\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Thalidomide-induced degradation of SALL4 via CRBN is responsible for disruption of human iPSC mesendoderm/lateral plate mesoderm differentiation; CRBN V388I mutation or SALL4 G416A mutation abrogates both SALL4 degradation and the teratogenic effects on LPM differentiation, establishing a CRBN-SALL4 axis in thalidomide teratogenicity.\",\n      \"method\": \"Engineered hiPSC lines with CRBN or SALL4 point mutations, differentiation assays, SALL4 protein stability assays\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean genetic rescue experiments with two independent mutations (CRBN and SALL4) in physiologically relevant human pluripotent stem cell model, multiple orthogonal methods\",\n      \"pmids\": [\"32071327\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CC-885 (a cereblon modulator) selectively promotes CRBN- and p97-dependent PLK1 ubiquitination and proteasomal degradation in non-small cell lung cancer cells, identifying PLK1 as a neosubstrate of CUL4-CRBN induced by CC-885.\",\n      \"method\": \"Ubiquitination assays, CRBN and p97 genetic depletion (rescue experiments), protein degradation assays, in vitro and in vivo tumor models\",\n      \"journal\": \"Molecular therapy oncolytics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic validation with CRBN/p97 knockdown and ubiquitination assays, single lab\",\n      \"pmids\": [\"32728610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CC-885 selectively induces CRBN-dependent ubiquitination and proteasomal degradation of CDK4 in multiple myeloma cells; CDK4 destruction by CC-885 decreases RB phosphorylation and suppresses E2F downstream gene expression.\",\n      \"method\": \"Ubiquitination assays, CRBN genetic ablation (rescue), protein degradation assays, RB phosphorylation readouts, cell cycle analysis\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRBN-dependent ubiquitination established by genetic rescue, single lab\",\n      \"pmids\": [\"33676183\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"A molecular glue degrader (MRT-31619) drives homo-dimerization of CRBN via two molecules assembling into a helix-like structure that mimics a neosubstrate G-loop degron, promoting CRBN self-ubiquitination and fast, potent, selective degradation by the ubiquitin-proteasome system. Cryo-EM structure of the CRBN homodimer reveals this unique mechanism.\",\n      \"method\": \"Cryo-EM structure determination, cellular degradation assays, quantitative proteomics, chemical biology\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cryo-EM structure of the homo-dimerization complex with functional degradation validation, single lab but orthogonal structural and biochemical methods\",\n      \"pmids\": [\"41258141\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CRBN interacts with and mediates AZD7762-dependent ubiquitination of BAG3; AZD7762-induced BAG3 degradation is CRBN-dependent and occurs through the ubiquitin-proteasome pathway, independent of Chk1 expression or activity.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, CRBN-dependent rescue experiments, western blot, cell viability assays\",\n      \"journal\": \"Anti-cancer drugs\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP and ubiquitination assay, single lab, limited mechanistic follow-up\",\n      \"pmids\": [\"37449977\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MORF4L1 (a chromatin-remodeling MRG family protein) is identified as an endogenous CRBN substrate; CRBN promotes MORF4L1 ubiquitination and degradation under physiological conditions, further enhanced by CC-885, as shown by Co-IP and structural modeling.\",\n      \"method\": \"Proteomic analysis, co-immunoprecipitation, structural modeling, protein stability assays\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — Co-IP and proteomics without full biochemical reconstitution, single lab, structural modeling is computational\",\n      \"pmids\": [\"39827217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP2 directly interacts with CRBN and promotes its deubiquitination and stabilization in senescent liver cancer cells, making them sensitive to CRBN-based PROTAC therapy.\",\n      \"method\": \"Co-immunoprecipitation, deubiquitination assays, genetic USP2 depletion, protein stability measurements\",\n      \"journal\": \"Gastroenterology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP showing USP2-CRBN interaction with functional CRBN stability readout, single lab\",\n      \"pmids\": [\"38262581\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Crystal structures of hydrolyzed thalidomide metabolites bound to the CRBN thalidomide-binding domain reveal binding mode of minimalistic CRBN effectors; a de-novo CRBN effector was designed from this scaffold that degrades the neosubstrate IKZF3 in cells.\",\n      \"method\": \"X-ray crystallography of CRBN-ligand complexes, cell-based IKZF3 degradation assays\",\n      \"journal\": \"Journal of medicinal chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structures informing binding mode with cell-based functional validation, single lab\",\n      \"pmids\": [\"31251063\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"A crystal structure of the DDB1/CRBN/lenalidomide complex with greater resolution than previously published was generated; dynamic modeling using this structure helped explain the differential impact of CRBN missense mutations on IMiD and CELMoD agent activity, including identification of mutations that can be overcome by more potent CELMoDs.\",\n      \"method\": \"X-ray crystallography (DDB1-CRBN-lenalidomide complex), structure-guided dynamic modeling, functional cell-based degradation assays, confirmatory mutagenesis experiments\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — high-resolution crystal structure with functional mutant validation, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"39841463\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CRBN is the substrate receptor of the CUL4-RBX1-DDB1-CRBN (CRL4CRBN) E3 ubiquitin ligase complex; it enantioselectively binds thalidomide and its IMiD derivatives at a defined pocket (established by crystal structures), and this binding reprograms the ligase to recruit and ubiquitinate a diverse set of neosubstrates—including IKZF1/3, CK1α, ZFP91, SALL4, ARID2, PLZF, and C2H2 zinc finger proteins—through a shared interface between the drug and a degron (often a G-loop or β-hairpin) on the neosubstrate; endogenous substrates (e.g., glutamine synthetase, MEIS2, ClC-2, BK channels) are recognized via a C-terminal cyclic imide degron generated by PCMT1; downstream, ubiquitylated substrates require p97/VCP for extraction and the E2 enzymes UBE2D3 (monoubiquitination priming) and UBE2G1 (K48 chain elongation) for efficient proteasomal degradation; USP15 antagonizes this degradation; CRBN additionally functions as a co-chaperone counteracting AHA1 to regulate HSP90 activity toward transmembrane protein clients, negatively regulates AMPK (via its N-terminal/C-terminal tail independent of the IMiD-binding site) to promote mTOR-dependent protein synthesis, inhibits TRAF6-dependent ubiquitination of ECSIT and Beclin-1, and controls BK channel ER retention—all constituting functions distinct from IMiD-induced neosubstrate degradation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CRBN is the substrate-recognition receptor of the CUL4-RBX1-DDB1-CRBN (CRL4CRBN) E3 ubiquitin ligase, where it dictates which proteins are ubiquitinated for proteasomal destruction [#0]. CRBN possesses a defined pocket that enantioselectively binds thalidomide and immunomodulatory imide drugs (IMiDs); drug occupancy creates a composite drug-CRBN surface that simultaneously blocks endogenous substrate binding (e.g., MEIS2) and reprograms the ligase to recruit neosubstrates [#0]. Crystal structures show that this neosubstrate interface engages a shared structural degron — a β-hairpin/G-loop presented by the kinase N-lobe of CK1α or the zinc-finger domains of IKZF1/IKZF3 [#1, #2] — and proteome-wide screening established that diverse C2H2 zinc-finger proteins, including ZFP91, dock at this permissive surface through a common mode [#3, #4]. The same drug-dependent recruitment extends to SALL4, ARID2, PLZF/ZBTB16 and additional targets accessed by cereblon modulators [#9, #12, #20]. Endogenous, drug-independent substrates are recognized through a distinct C-terminal cyclic imide degron installed on asparagine residues by PCMT1, which co-regulates metabolic enzymes such as glutamine synthetase with CRBN [#18]. Productive degradation of CRL4CRBN-ubiquitinated substrates requires the E2 enzymes UBE2D3 (monoubiquitin priming) and UBE2G1 (K48 chain elongation), CUL4 neddylation, and p97/VCP-mediated extraction, while USP15 deubiquitinates substrates to antagonize their turnover [#5, #8, #11]. Beyond its ligase function, CRBN ubiquitinates and controls trafficking of ion channels: it retains BK channels in the ER, with loss of CRL4A(CRBN) activity lowering seizure threshold in mice, and it promotes degradation of ClC-2 chloride channels [#6, #17]. CRBN also acts as an HSP90 co-chaperone that counteracts AHA1 for transmembrane-client quality control [#10], and negatively regulates AMPK through its N- and C-terminal regions independently of the IMiD pocket to sustain mTOR-dependent translation [#14, #16]. A C-terminal truncation mutant that fails to support mTOR-dependent translation is linked to human mild mental retardation [#14].\",\n  \"teleology\": [\n    {\n      \"year\": 2013,\n      \"claim\": \"Established the first molecular consequence of CRBN engagement by IMiDs — that lenalidomide/pomalidomide redirect CRL4CRBN to destroy specific transcription factors — answering how these drugs exert immunomodulatory effects.\",\n      \"evidence\": \"Co-IP, ubiquitination assays, proteasome rescue, and in vivo human pharmacodynamic detection of Aiolos loss\",\n      \"pmids\": [\"24328678\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not provide the structural basis of drug-induced recruitment\", \"Endogenous substrate repertoire unaddressed\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Defined CRBN as the substrate receptor of CRL4CRBN and showed atomically that IMiD binding both blocks an endogenous substrate (MEIS2) and recruits neosubstrates (IKZF1/3), unifying drug binding and substrate reprogramming.\",\n      \"evidence\": \"X-ray crystallography of DDB1-CRBN-IMiD complexes plus unbiased substrate screen and ubiquitination assays\",\n      \"pmids\": [\"25043012\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve a ternary drug-CRBN-neosubstrate structure\", \"Scope of neosubstrate degron not generalized\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Revealed CRBN ligase functions beyond IMiD biology — ubiquitination and ER retention of BK channels, and a drug-independent AMPK-mTOR translational role with a disease-linked truncation mutant.\",\n      \"evidence\": \"Mouse genetic models, electrophysiology, AMPK/mTOR readouts, and rescue with WT vs. patient mutant CRBN\",\n      \"pmids\": [\"24845235\", \"24993823\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"AMPK regulation mechanism (which domain, direct vs. indirect) not defined at this stage\", \"BK degron not characterized\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Solved the ternary CRBN-lenalidomide-CK1α structure, showing CRBN and the drug jointly form the neosubstrate interface engaging a β-hairpin degron, explaining selective del(5q) MDS efficacy.\",\n      \"evidence\": \"2.45 Å ternary crystal structure with in vitro binding and mutagenesis\",\n      \"pmids\": [\"26909574\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Generality of the degron mode across other substrate classes untested here\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Generalized the neosubstrate concept by identifying ZFP91 via unbiased proteomics and linking it to an IKZF-related zinc-finger degron, and established that p97/VCP extraction is required downstream of ubiquitination.\",\n      \"evidence\": \"pSILAC mass spectrometry, ZnF mutagenesis, and p97 inhibition/dominant-negative rescue across multiple substrates\",\n      \"pmids\": [\"28530236\", \"28320958\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"E2 enzyme identities not yet defined\", \"Mechanism of p97 substrate handoff unresolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Systematized the degron rules by mapping the C2H2 zinc-finger degron space and defined the enzymatic machinery (UBE2D3 priming, UBE2G1 elongation, neddylation control) plus an in vivo CRBN residue (I391V/V388) sufficient to confer drug sensitivity and teratogenicity.\",\n      \"evidence\": \"Proteome-wide degradation screen with multiple ternary crystal structures; genome-wide CRISPR screen; knock-in mouse model\",\n      \"pmids\": [\"30385546\", \"30042095\", \"30064974\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Endogenous physiological degron chemistry still unknown\", \"How E2 selection is achieved mechanistically unresolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Broadened the substrate landscape (SALL4, ARID2, PLK1, CDK4) and showed subcellular distribution of CRBN, via KPNB1-mediated nuclear import, governs which substrates can be degraded; linked SALL4 degradation directly to thalidomide teratogenicity.\",\n      \"evidence\": \"Engineered hiPSC point-mutant rescue, proteomics/Co-IP, KPNB1 knockdown with fractionation and degradation assays\",\n      \"pmids\": [\"32071327\", \"32958952\", \"32132601\", \"32728610\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Most neosubstrates validated in single-lab cell systems\", \"Endogenous functions of these substrates under CRBN control incompletely mapped\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined antagonists and non-ligase functions: USP15 reverses CRL4CRBN ubiquitination of substrates; CRBN acts as an HSP90 co-chaperone counteracting AHA1; and AMPK regulation was shown to operate independently of the IMiD pocket via N-/C-terminal regions.\",\n      \"evidence\": \"Deubiquitination/stability assays, reciprocal Co-IP and cell-surface proteomics, and domain-deletion AMPK binding/activity assays\",\n      \"pmids\": [\"34583995\", \"33571422\", \"34073624\", \"31620128\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Non-ligase functions largely single-lab\", \"Structural basis of CRBN-HSP90 and CRBN-AMPK interactions undefined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified the endogenous degron chemistry — PCMT1 generates C-terminal cyclic imide degrons that CRBN recognizes — and demonstrated a homo-dimerization molecular-glue mechanism inducing CRBN self-degradation, plus high-resolution structures rationalizing clinical CRBN mutations.\",\n      \"evidence\": \"In vitro enzymatic reconstitution with cellular/in vivo validation (PCMT1); cryo-EM of CRBN homodimer; high-resolution DDB1-CRBN-lenalidomide crystallography with dynamic modeling\",\n      \"pmids\": [\"41461925\", \"41258141\", \"39841463\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full endogenous substrate repertoire defined by cyclic imide degron incomplete\", \"Physiological role of CRBN self-degradation unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How CRBN's diverse non-ligase activities (HSP90 co-chaperone, AMPK regulation, mitochondrial/autophagy control) are integrated with its CRL4 receptor function, and the full physiological substrate set defined by the PCMT1 cyclic imide degron, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified structural/cellular model linking ligase and non-ligase roles\", \"Endogenous substrate landscape not comprehensively mapped\", \"Several low-confidence substrate/regulator findings (BAG3, MORF4L1, USP2) await independent validation\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 6, 17]},\n      {\"term_id\": \"GO:0016874\", \"supporting_discovery_ids\": [0, 5, 8]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 2, 3]},\n      {\"term_id\": \"GO:0044183\", \"supporting_discovery_ids\": [10]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [14, 16]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [13]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [13]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [6, 17]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [15]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 1, 5, 8]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [6, 14, 20]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [14, 16]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [15]}\n    ],\n    \"complexes\": [\n      \"CRL4CRBN (CUL4-RBX1-DDB1-CRBN E3 ubiquitin ligase)\",\n      \"CRBN-AHA1-HSP90 chaperone axis\"\n    ],\n    \"partners\": [\n      \"DDB1\",\n      \"CUL4A\",\n      \"UBE2G1\",\n      \"UBE2D3\",\n      \"USP15\",\n      \"HSP90\",\n      \"AHA1\",\n      \"KPNB1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":9,"faith_pct":88.88888888888889}}