## ATP6V0E2
- **UniProt:** Q8NHE4 · **batch:** proteostasis-batch-2026-06-07 · **review status:** COMPLETE
- **PN placement:** two ALP leaves "V0 lysosomal v-ATPase proton pump component" (under Nutrient sensing; and under Lysosomal acidification). **PN-node mapping:** leaf→GO:0046610 lysosomal V0 domain (more_specific_than_existing_goa); leaf→GO:0033179 V0 domain (already_in_goa_exact); type→GO:0007042 lysosomal lumen acidification (more_specific_than_existing_goa). Higher ancestors no_mapping/context_only.
- **Consistency:** Review and PN agree on the core identity: e2 is an accessory V0-sector membrane subunit (PMID:17350184 yeast complementation), part_of vacuolar V0 domain (GO:0000220/GO:0033179, both ACCEPT) and involved in proton transport/vacuolar acidification. The review carries multiple TAS lysosomal-membrane annotations (Reactome), so a lysosomal context is genuinely supported here (unlike the strictly plasma-membrane isoforms). PN-projection terms GO:0046610, GO:0007042, GO:0033179 all verified real via OLS. No contradictions. Minor: PN Notes text (shared template across the V-ATPase batch) is appropriate for e2 since it is a true V0 subunit.
- **PN story / NEW pressure:** PN asserts lysosomal V0-domain componency + lysosomal lumen acidification — more specific than the review's vacuolar-level terms. GO:0046610 (child of GO:0000220) and GO:0007042 (child of GO:0007035, which the review ACCEPTs as ISS) are defensible narrowings; e2 has lysosomal-membrane TAS support. The review did NOT add these. **ADD GO:0046610 + GO:0007042 — defensible (verified real), but mark as project-context narrowings of the already-accepted vacuolar terms.**
- **Mapping strategy:** Gene legitimately supports both V0 leaves. Lysosomal projection is reasonable for e2 (broader tissue distribution: heart/brain/kidney; lysosomal Reactome+altname evidence). Projections narrow existing GOA, not over-broad. No node-mapping change needed.
- **Evidence alignment:** PN cites only generic V-ATPase/mTORC1 review titles; review is better-sourced with the gene-specific PMID:17350184 (e-subunit essentiality) plus Reactome lysosomal reactions. Divergence is review-favorable; no conflict.
- **Verdict:** CONSISTENT — lysosomal projection defensible for this V0 subunit; PN terms verified real. Optional: add GO:0046610/GO:0007042 to review as conservative narrowings.