# ATP4A

Source: https://onco.cc/targets/atp4a/  
OnCo record `atp4a` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

ATP4A (Potassium-transporting ATPase alpha chain 1) is a gene. The public catalogues list it as a drug target, and an approved or late-stage drug is recorded against it. Tied to Gastric & gastro-oesophageal junction cancer and Non-Hodgkin lymphoma.

## Summary

The catalytic subunit of the gastric H(+)/K(+) ATPase pump which transports H(+) ions in exchange for K(+) ions across the apical membrane of parietal cells. Uses ATP as an energy source to pump H(+) ions to the gastric lumen while transporting K(+) ion from the lumen into the cell. Remarkably generates a million-fold proton gradient across the gastric parietal cell membrane, acidifying the gastric juice down to pH 1.

Open Targets scores its association with cancer at 0.58 (direct and indirect evidence; datatypes literature 0.45, animal model 0.65, genetic association 0.00, clinical 0.91).

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: ATPase H+/K+ transporting subunit alpha; Potassium-transporting ATPase alpha chain 1; ATP6A
- Tags: cancer-genes-wave
- Symbol: ATP4A
- Class: other
- Biology: The catalytic subunit of the gastric H(+)/K(+) ATPase pump which transports H(+) ions in exchange for K(+) ions across the apical membrane of parietal cells. Uses ATP as an energy source to pump H(+) ions to the gastric lumen while transporting K(+) ion from the lumen into the cell. Remarkably generates a million-fold proton gradient across the gastric parietal cell membrane, acidifying the gastric juice down to pH 1. Within a transport cycle, the transfer of a H(+) ion across the membrane is coupled to ATP hydrolysis and is associated with a transient phosphorylation that shifts the pump conformation from inward-facing (E1) to outward-facing state (E2). The release of the H(+) ion in the stomach lumen is followed by binding of K(+) ion converting the pump conformation back to the E1 state. Location: Apical cell membrane (UniProt). Locus 19q13.12 (HGNC).
- Where found: Gastric & gastro-oesophageal junction cancer: Open Targets association 0.56 with gastric cancer (MONDO_0001056); Non-Hodgkin lymphoma: Open Targets association 0.52 with non-Hodgkin lymphoma (MONDO_0018908)

## Notes

- Written by scripts/fetch-cancer-genes.ts from CIViC, Open Targets, IntOGen, HGNC and UniProt; the function text is UniProt's, condensed and in UK spelling. Roles: Open Targets known-drug datatype score 0.91. Evidence tier "approved-drug" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:819: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:819
- UniProt P20648: https://www.uniprot.org/uniprotkb/P20648/entry
- NCBI Gene 495: https://www.ncbi.nlm.nih.gov/gene/495
- Ensembl ENSG00000105675: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000105675

## Connected records

- collections: [Open Targets Platform](https://onco.cc/collections/open-targets/)
- cancers: [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/)

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JSON: https://onco.cc/api/v1/entities/atp4a.json