## ABTB1
- **UniProt:** Q969K4 · **batch:** proteostasis-batch-2026-06-03 · **review status:** COMPLETE
- **PN placement:** `UPS|E3 ubiquitin and UBL ligases|Cul3 substrate receptor|BTB-BACK|ankyrin` ; **PN-node mapping:** subtype/type (`BTB-BACK`,`ankyrin`)=no_mapping; group `Cul3 substrate receptor`=mapped→**GO:1990756 ubiquitin-like ligase-substrate adaptor activity** (new_to_goa); class `E3...ligases`=context_only (GO:0061630 too_broad); branch UPS=no_mapping.
- **Consistency:** Consistent in evidence, divergent in conclusion (deliberately). Deep research/notes: ABTB1 = cytoplasmic ankyrin+BTB/POZ protein, CUL3 interactor (UniProt NbExp=5), BPOZ/PTEN-responsive growth suppressor; **no validated CRL3 substrate**. The review accepts cytoplasm/cytosol, MODIFIES generic ligase-complex→GO:0031463 Cul3-RING ubiquitin ligase complex and protein binding→GO:0097602 cullin family protein binding, and **declines** the PN-projected GO:1990756 substrate-adaptor activity because no substrate-bridging assay exists. PN (substrate-receptor activity) vs review (CUL3 binding + CRL3 membership, no adaptor activity) is an evidence-based divergence, not a contradiction — the review is the more conservative, better-justified position.
- **PN story / NEW pressure:** PN asserts substrate-adaptor (receptor) activity via GO:1990756 (verified real; def. "usually mediated by F-box/BTB/POZ proteins"). Architecturally plausible but unproven for ABTB1 (no substrate). The review instead adds two verified, better-supported terms — **GO:0031463** (Cul3-RING ubiquitin ligase complex; verified real) and **GO:0097602** (cullin family protein binding; verified real) — as proposed replacements. Conclusion: PN's adaptor-activity claim **over-reaches**; the defensible additions are GO:0031463/GO:0097602, **already captured** in the review as MODIFY replacements.
- **Mapping strategy:** Group node `Cul3 substrate receptor`→GO:1990756 should be treated as non-propagating for ABTB1 until a substrate-bridging assay exists; the review's CRL3-complex membership (GO:0031463) is the appropriate landing point instead. Class-node GO:0061630 correctly context_only. The PN MF projection is broader/stronger than evidence supports — analogous to the rejected-projection precedent.
- **Evidence alignment:** PN reference titles: PMID:15071497/rev and PMID:23912815/rev (Cul3/BTB substrate-receptor reviews). The review instead anchors CUL3 evidence on PMID:21145461 (CRL-network proteomics) + UniProt IntAct (CUL3 NbExp=5); the two PN review-PMIDs are not in the review reference list. Mild divergence (different supporting reviews) but same CRL3 biology.
- **Verdict:** Consistent; PN substrate-adaptor activity correctly held back (no substrate), review adds verified CRL3 complex + cullin-binding terms. **Recommended edits:** [MAP] Keep GO:1990756 non-propagating for ABTB1 pending substrate evidence (review's GO:0031463/GO:0097602 are the correct landing terms). Optional [REF]: consider adding PMID:15071497 / PMID:23912815 (PN-cited Cul3 reviews) to the review references for completeness.