## DDB2
- **UniProt:** Q92466 · **batch:** proteostasis-batch-2026-06-13 · **review status:** COMPLETE
- **PN placement:** `UPS|E3 ubiquitin and UBL ligases|Cul4A/Cul4B substrate receptor|WD40|other` ; **PN-node mapping:** group "Cul4A/Cul4B substrate receptor"=mapped, ok_for_propagation, GO:1990756 (substrate-adaptor MF); subtype/type=no_mapping; projected GO:1990756 goa_status=new_to_goa.
- **Consistency:** Consistent on the substrate-receptor (DCAF) identity. Deep research, review and PN all describe DDB2 as the WD40 substrate-recognition receptor of CRL4(DDB2), plus the UV-DDB lesion sensor. Minor divergence in MF choice (see below). No biological contradiction.
- **PN story / NEW pressure:** PN projects GO:1990756 (substrate-adaptor MF) as new_to_goa — and indeed GOA has no GO:1990756 (it has GO:0004842 contributes_to and GO:0003684 damaged-DNA binding; confirmed in goa.tsv). GO:1990756 is real (OLS) and biologically appropriate for DDB2 as a DCAF receptor. Verdict: ADD is defensible. The review instead represents the receptor MF as GO:0004842 (ubiquitin-protein transferase, contributes_to) and the sensor MF as GO:0003684; it does NOT propose GO:1990756.
- **Mapping strategy:** Correct category (substrate receptor → GO:1990756), unlike DDB1. DDB2 is genuinely the DCAF receptor of CRL4(DDB2), so GO:1990756 is well placed and narrower than the generic existing terms. Node status/scope fine.
- **Evidence alignment:** PN row lists no references; the review is richly evidenced (PMID:12732143 ligase activity IDA; 16473935 H2A ubiquitination; 22334663 CUL4B complex; 19109893 UV-DDB structure; etc.), all marked VERIFIED. No conflict; PN simply under-cites.
- **Verdict:** Consistent; PN GO:1990756 (receptor) is correctly categorized and a defensible add. **Recommended edits:** [YAML] consider adding GO:1990756 to DDB2 as the explicit DCAF substrate-receptor MF (complements existing GO:0004842 contributes_to), aligning with the PN projection.