## ATP6V0A4
- **UniProt:** Q9HBG4 · **batch:** proteostasis-batch-2026-06-03 · **review status:** COMPLETE
- **PN placement:** two ALP leaves "V0 lysosomal v-ATPase proton pump component". **PN-node mapping:** leaf→GO:0046610 (more_specific_than_existing_goa); leaf→GO:0033179 (already_in_goa_exact); type→GO:0007042 lysosomal lumen acidification (more_specific_than_existing_goa).
- **Consistency:** Deep research/notes, review, and PN diverge in emphasis. ATP6V0A4 is the a4 V0 a-subunit whose best-supported human biology is **renal apical-plasma-membrane** urinary acidification and inner-ear function (dRTA, hearing loss; PMID:10973252, PMID:14638902, PMID:12414817), NOT primarily lysosomal. The review does NOT add GO:0046610 or GO:0007042; it keeps lysosomal membrane KEEP_AS_NON_CORE (HDA, PMID:17897319) and explicitly questions the PN lysosomal projection.
- **PN story / NEW pressure:** PN projects the same lysosomal V0/acidification terms it gives the c''/d2 subunits, but a4 lacks direct isoform-specific lysosomal-acidification evidence. The review's restraint is correct: **the lysosomal projection over-reaches for a4** (the a-subunit isoforms are differentially targeted; a4 → apical PM, not lysosome). proposed_new_terms empty; lysosomal terms NOT added. **Over-reaches / correctly declined in review.**
- **Mapping strategy:** This gene *should* change the node treatment: ATP6V0A4 is a weak/contraindicated member of the "lysosomal V0 component" leaf. GO:0046610/GO:0007042 are narrower than what a4 evidence supports and risk a false lysosome-specific claim — the TOMM20/RAB7A "leaf doesn't fit this member" pattern. The leaf mapping is fine for c''/d2 but should be flagged not-for-propagation to a4.
- **Evidence alignment:** PN cites generic V-ATPase/mTORC1 titles (none a4-specific); review cites a rich a4-specific renal/inner-ear literature (PMID:10973252, 12649290, 14638902, 17360703, 12414817) entirely absent from the PN row. Clear divergence; review is far better sourced.
- **Verdict:** PN LYSOSOMAL PROJECTION OVER-REACHES for a4 (renal-apical, not lysosomal); review correctly declined. **Recommended edits:** [MAP] flag GO:0046610 + GO:0007042 leaf/type projections as not_for_propagation to ATP6V0A4 (no a4-specific lysosomal evidence; isoform is apical-PM targeted); keep GO:0033179 (V0 domain, already in GOA).