Potassium-transporting ATPase subunit beta (ATP4B) (ATP4B)

The Gastric H+/K+-ATPase beta subunit (ATP4B) is a type II transmembrane glycoprotein that serves as the essential accessory subunit for the gastric proton pump (UniProt: P51164). It plays a critical role in the maturation, stable assembly, and apical membrane targeting of the catalytic alpha subunit (ATP4A) within gastric parietal cells (PubMed: 10913254). The functional holoenzyme is responsible for the final step of gastric acid secretion, transporting protons into the stomach lumen in exchange for potassium ions via ATP hydrolysis (StatPearls: NBK546650). Clinical targeting of this enzyme complex is the gold standard for treating acid-related disorders, including gastroesophageal reflux disease (GERD) and peptic ulcers (PubMed: 26307015). While drugs like proton pump inhibitors (PPIs) and potassium-competitive acid blockers (P-CABs) primarily target the alpha subunit's catalytic cycle, the beta subunit is indispensable for the pump's structural integrity and overall acid-secreting capacity (PubMed: 11566453). Notably, the beta subunit is a major autoantigen in autoimmune gastritis and pernicious anemia, where autoantibodies against the subunit lead to parietal cell destruction and vitamin B12 malabsorption (PubMed: 15273414).

Other names

Gastric H+/K+ ATPase beta subunitATP4BProton pump beta subunitH-K-ATPase beta subunitPotassium-transporting ATPase subunit betaATPase H+/K+ transporting subunit beta

Inhibition of the gastric H+/K+-ATPase enzyme complex, which prevents the exchange of intracellular H+ for extracellular K+, thereby halting the final step of gastric acid production.