## CHMP4B
- **UniProt:** Q9H444 · **batch:** proteostasis-pr-1217 · **review status:** COMPLETE
- **PN placement:** `ALP → Autophagosome closure maturation and lysosome fusion → Sealing of autophagophore membrane → ESCRT-III complex component` AND `ALP → Microautophagy → General microautophagy machinery → ESCRT-III complex component` (2 rows)
- **PN-node mapping:** type = `mapped`/`ok_for_propagation` → GO:0000815 ESCRT III complex (already in GOA); "Sealing" group = `mapped` → GO:0000045 autophagosome assembly (`more_specific_than_existing_goa`); both classes `context_only`/`too_broad` (GO:0016236 macroautophagy, GO:0016237 microautophagy); branch `no_mapping`.
- **Consistency:** Strong. Deep-research (falcon), review, PN, and mapping all agree CHMP4B is the dominant Snf7-family ESCRT-III core subunit with a genuine, gene-specific autophagy link: human-neuron hSnf7-2 knockdown causes autophagosome accumulation (PMID:21975012); STX13/phagophore→autophagosome maturation (PMID:24095276). No contradictions.
- **PN story / NEW pressure:** PN's "Sealing of autophagophore" projects GO:0000045 autophagosome assembly (verified real via OLS) as more specific than current GOA. The review captures the autophagy axis at a sibling altitude — GO:0097352 autophagosome maturation + GO:0016236 macroautophagy (both KEEP_AS_NON_CORE, in core_functions) — but does NOT carry GO:0000045. For CHMP4B specifically, the closure/sealing role is the best-supported of the five paralogs, so GO:0000045 is a defensible ADD as non-core. **ADD GO:0000045 autophagosome assembly (non-core).**
- **Mapping strategy:** No change needed. CHMP4B membership reinforces (does not alter) the leaf→GO:0000815 / group→GO:0000045 calls; the conservative class-level `context_only` holds. PN projection is appropriately narrower than the existing macroautophagy term, unlike the rejected TOMM20/HSPA8/RAB7A broader projections.
- **Evidence alignment:** Partial. PN cites two reviews (Cells "Key Regulators of Autophagosome Closure"; tandfonline mitophagy sealing). Review cites primary literature (PMID:18209100, 21975012, 17984323, 24095276) — same ESCRT-in-autophagy theme, different specific papers. GO:0000815 IBA original_reference is GO_REF:0000033, not the PN review.
- **Verdict:** Consistent; well-handled. **Recommended edits:** add GO:0000045 autophagosome assembly as a NEW non-core annotation (PMID:21975012, 24095276) to close the one gap vs the PN projection.