## ATP6V1G3
- **UniProt:** Q96LB4 · **batch:** proteostasis-batch-2026-06-07 · **review status:** COMPLETE
- **PN placement:** two ALP leaves "V1 lysosomal v-ATPase proton pump component" (Nutrient sensing; Lysosomal acidification). **PN-node mapping:** leaf→GO:0046612 lysosomal V1 domain (more_specific_than_existing_goa); leaf→GO:0033176 V-type ATPase complex (entailed_by_goa_closure); type→GO:0007042 lysosomal lumen acidification (new_to_goa).
- **Consistency:** CONFLICT on compartment. Review/notes establish G3 as the kidney-enriched (plus inner-ear) G isoform that assembles the tissue-specific pump (a4/B1/C2/d2) at the **apical plasma membrane** of collecting-duct intercalated cells for luminal acid secretion (IDA plasma membrane PMID:17360703; ATPase binding to a4/a1, IPI). The review explicitly KEEPs_AS_NON_CORE the IBA synaptic-vesicle/synaptic-vesicle-acidification annotations as generic family transfers irrelevant to G3, and asserts NO lysosomal role. PN places G3 under "lysosomal v-ATPase" and projects lysosomal lumen acidification — contradicting the plasma-membrane renal biology. PN Notes template ("pumps protons into the lysosome") mis-frames this isoform.
- **PN story / NEW pressure:** PN's lysosomal lumen acidification (new_to_goa) OVER-REACHES for G3; evidenced compartment is apical plasma membrane (GO:0005886, IDA, ACCEPT), function is renal luminal acid secretion. GO:0046612/GO:0007042 verified real but wrong specialization. **Lysosomal projection should NOT be propagated.**
- **Mapping strategy:** Tissue-restricted plasma-membrane isoform; lysosomal projection over-broad (TOMM20/HSPA8/RAB7A precedent). **[MAP]** flag G3 as an exception — safe targets are vacuolar V1 domain/complex (GO:0000221/GO:0016471) + plasma-membrane acid-secretion context already in the review; the specific G3-a-subunit ATPase-binding (GO:0051117) is the mechanistically informative core, not lysosomal acidification.
- **Evidence alignment:** No overlap. PN cites generic reviews; review cites G3-specific PMID:17360703 (V1-V0 G-a linkage, kidney expression, plasma membrane) and PMID:12384298 (kidney-specific isoform). Review strongly better-evidenced.
- **Verdict:** OVER-REACH — PN lysosomal projection wrong-compartment for this apical-plasma-membrane kidney isoform. **Recommended edits:** [MAP] exempt ATP6V1G3 from lysosomal-acidification/lysosomal-V1 projection; restrict to vacuolar V1 complex + plasma-membrane/renal acid-secretion terms already in the review.