## P4HA1
- **UniProt:** P13674 · **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 all describe the catalytic alpha-1 subunit of collagen prolyl 4-hydroxylase (C-P4H, EC 1.14.11.2), the alpha2-beta2 heterotetramer with P4HB/PDI, ER-lumenal. PN "collagen processing/folding" placement matches the rate-limiting 4-Hyp modification that stabilizes the triple helix.
- **PN story / NEW pressure:** PN asserts collagen biosynthetic process (GO:0032964) as new_to_goa — and indeed P4HA1 GOA has NO collagen-process BP term (only GO:0030199 collagen fibril organization, kept non-core). The review independently flags this gap in proposed_new_terms, recommending GO:0018401 peptidyl-proline hydroxylation to 4-hydroxy-L-proline / GO:0032964. Both GO:0032964 and GO:0018401 verified real via OLS. Conclusion: genuine ADD; PN projection and review agree a BP term is missing. GO:0018401 (direct catalytic BP) is arguably more precise than GO:0032964, but GO:0032964 is the better cross-gene PN-group term.
- **Mapping strategy:** Correct. Catalytic subunit; group-level GO:0032964 is appropriate and not over-broad (it is narrower than the unmapped parent class). No change to node needed.
- **Evidence alignment:** PN dossier is mapping-only (no titles). Review core evidence: IDA PMID:9211872, TAS PMID:2543975 (cloning), structural PMID:24207127. Review adds many cancer/fibrosis refs (PMID:39568592, 38907027, 35368589 MBL substrate, etc.) absent from PN — expected divergence; PN focuses on canonical collagen biochemistry, review on full functional literature. Core biochemistry aligns.
- **Verdict:** Consistent; PN GO:0032964 ADD is genuinely new to GOA and corroborated by the review's own proposed_new_terms (BP gap real).