## PPIB
- **UniProt:** P23284 · **batch:** proteostasis-batch-2026-06-07b · **review status:** COMPLETE (exhaustive; ~55 annotations, notes present, no provider deep-research file)
- **PN placement (2 rows):** `ER proteostasis|Folding enzyme|Peptidyl-prolyl isomerases|Cyclophilin type` and `ER proteostasis|Maturation and folding of specific substrates|ER collagen processing and folding` ; **PN-node mapping:** type+group (PPIases / Cyclophilin type)→GO:0003755 peptidyl-prolyl cis-trans isomerase activity (mapped/ok_for_propagation, already_in_goa_exact); collagen group→GO:0032964 collagen biosynthetic process (mapped/ok_for_propagation, new_to_goa); class/branch→no_mapping.
- **Consistency:** Fully consistent. Review, notes, and UniProt agree PPIB is a genuine ER-lumenal cyclophilin-type PPIase (EC 5.2.1.8, CsA-inhibited) and a component of the P3H1/CRTAP/PPIB collagen prolyl-3-hydroxylation complex; LoF causes osteogenesis imperfecta type IX. Both PN mappings align with the review's two core functions.
- **PN story / NEW pressure:** Two projections. (1) GO:0003755 (VERIFIED real) is already in GOA exact (IEA/IDA/ISS/NAS — confirmed in goa.tsv) and ACCEPTed as core — already captured, correct. (2) GO:0032964 collagen biosynthetic process (VERIFIED real via OLS) is NOT in PPIB GOA (confirmed: GOA has only collagen binding GO:0005518 and bone development GO:0060348) — a defensible NEW BP capturing PPIB's collagen-maturation role. Conclude: GO:0003755 already captured; GO:0032964 = ADD (defensible, real, novel-to-GOA).
- **Mapping strategy:** Mappings are appropriately scoped — narrow, member-supported MF/BP terms, not over-broad umbrellas (unlike the TOMM20/HSPA8/RAB7A rejections). GO:0032964 is well-matched to PPIB's documented collagen-processing function and bone-disease genetics. No mapping change needed.
- **Evidence alignment:** PN node carries no reference titles, but review evidence directly supports both stories: PMID:20676357 / PMID:2000394 (PPIase activity, VERIFIED), PMID:39245686 (P3H1/CRTAP/PPIB collagen complex) and PMID:20089953 (PPIB-null OI) for the collagen/bone biology. Note the nuanced NOT|protein folding and NOT|regulation of PTM (PMID:20089953: PPIB-null OI has normal collagen folding) — these qualify, but do not contradict, the broader collagen-biosynthesis role.
- **Verdict:** CONSISTENT — GO:0003755 already captured (correct); GO:0032964 is a sound NEW addition. **Recommended edits:** [YAML] consider adding GO:0032964 collagen biosynthetic process (involved_in) to PPIB existing/proposed terms, supported by PMID:39245686 + OI9 genetics, to align the review with the defensible PN projection.