## CRBN
- **UniProt:** Q96SW2 · **batch:** proteostasis-batch-2026-06-07 · **review status:** COMPLETE
- **PN placement:** `Ubiquitin Proteasome System | E3 ubiquitin and UBL ligases | Cul4A/Cul4B substrate receptor | non-WD40 | LON, Yippee, DOC` ; **PN-node mapping:** group (Cul4A/Cul4B substrate receptor)=mapped, scope=ok_for_propagation_to_go, GO:1990756 ubiquitin-like ligase-substrate adaptor activity; class (E3 ligases)=context_only, scope=too_broad_to_propagate, GO:0061630 ubiquitin protein ligase activity; subtype/type/branch = no_mapping
- **Consistency:** Consistent and well-judged. Review describes CRBN as the substrate-recognition subunit of CRL4(CRBN) (DDB1/CUL4A or CUL4B/RBX1), with the CULT domain as the IMiD/molecular-glue/neosubstrate-binding module. PN annotation (Cul4 substrate receptor, LON/Yippee/DOC domain family; auxiliary domains IPR003111/IPR004910/IPR004939; ref 17588513) and PN-node mapping align with this exactly.
- **PN story / NEW pressure:** PN projects GO:1990756 ubiquitin-like ligase-substrate adaptor activity (verified real OLS; definition "brings together a ubiquitin-like ligase and its substrate"). This is NOT in the current GOA (grep confirms absence) — GOA's only MF is bare GO:0005515. The review independently proposes the SAME term as a NEW IDA annotation (from PMID:26909574). Perfect convergence. Conclusion: **ADD** GO:1990756 — defensible, verified, and the precise adaptor MF CRBN lacks in GOA.
- **Mapping strategy:** Correct, and notably careful re the task's CRBN caution. The PN deliberately avoids over-broad CRL4 ligase terms: it marks the E3-ligase class as context_only / too_broad_to_propagate (GO:0061630 not propagated) and propagates only the substrate-receptor group → GO:1990756 (adaptor, not catalytic ligase). This matches the review, which represents CRBN as adaptor (GO:1990756) + complex membership (GO:0031464/0031465), never as the catalytic ligase. No broadening problem.
- **Evidence alignment:** PN cites 17588513 (CRBN-domain/cereblon ref). Review's adaptor-MF evidence is PMID:26909574 (+ PMID:25108355, PMID:20223979). Different but compatible anchors, both establishing the substrate-receptor/adaptor role; high-throughput GO:0005515 PMIDs correctly marked over-annotated. No conflict.
- **Verdict:** Consistent; PN GO:1990756 adaptor mapping verified, matches review's NEW term, and correctly avoids over-broad CRL4 ligase terms. **Recommended edits:** none (PN and review already converge on GO:1990756).