## P4HA2
- **UniProt:** O15460 · **batch:** proteostasis-batch-2026-06-11 · **review status:** COMPLETE
- **PN placement:** `ER proteostasis | Maturation and folding of specific substrates | ER collagen processing and folding` ; **PN-node mapping:** group=mapped, scope=ok_for_propagation_to_go, GO=GO:0032964 collagen biosynthetic process (class/branch=no_mapping). Projection goa_status=new_to_goa.
- **Consistency:** Consistent. Review, deep research, PN annotation, and mapping describe the type II catalytic alpha-2 subunit of C-P4H (EC 1.14.11.2), alpha2-beta2 with P4HB, ER-lumenal; collagen 4-Hyp formation for triple-helix stability. PN placement matches. The review additionally surfaces non-canonical substrates (mTOR Pro2341 hydroxylation PMID:38654109; SUFU PMID:38909089) flagged non-core pending confirmation — these do not contradict the PN canonical-collagen placement.
- **PN story / NEW pressure:** PN asserts GO:0032964 as new_to_goa; P4HA2 GOA has NO BP term at all (verified via goa.tsv). The review's proposed_new_terms explicitly recommends adding GO:0019471/GO:0018401/GO:0032964. GO:0032964 and GO:0018401 verified real via OLS. Conclusion: genuine ADD, fully corroborated by the review. Defensible.
- **Mapping strategy:** Correct. Catalytic subunit; group-level GO:0032964 appropriate, narrower than the unmapped class node. No node change required. (Note GO:0009055 electron transfer activity in GOA was MARK_AS_OVER_ANNOTATED in the review — unrelated to the PN MF/BP projection.)
- **Evidence alignment:** PN dossier mapping-only. Review core: IDA/TAS PMID:9211872 (type II tetramer characterization), authoritative review PMID:32969070. Many cancer/non-canonical-substrate refs (PMID:38654109, 38909089, 38857058, 41096640) are beyond the PN canonical-biochemistry scope — expected divergence. Core collagen biochemistry aligns.
- **Verdict:** Consistent; PN GO:0032964 ADD genuinely new to GOA and matches the review's own proposed BP terms (BP gap real).