ATP4A
ATP4A is the catalytic alpha subunit of the gastric H+/K+ ATPase, the proton pump that drives acid secretion in the stomach. Also known as ATP6A, it belongs to the P-type cation-transporting ATPase family. Browse Assay Genie's current range of ATP4A research reagents below, or read on for the biology behind the target.
ATP4A is the catalytic subunit of the gastric H+/K+ ATPase pump. It transports H+ ions in exchange for K+ ions across the apical membrane of parietal cells, using ATP as its energy source to pump H+ into the gastric lumen while carrying K+ from the lumen into the cell. The pump generates a million-fold proton gradient across the parietal cell membrane, acidifying gastric juice to around pH 1.
Each transport cycle couples the transfer of an H+ ion to ATP hydrolysis. A transient phosphorylation shifts the pump from the inward-facing (E1) conformation to the outward-facing (E2) state. Release of H+ into the stomach lumen is followed by K+ binding, which converts the pump back to the E1 state.
The ATP4A gene encodes a protein of the P-type cation transport ATPase family (TC 3.A.3), type IIC subfamily. According to NCBI Gene, the gastric H+, K+-ATPase is a heterodimer of a high molecular weight catalytic alpha subunit, encoded by ATP4A, and a smaller, heavily glycosylated beta subunit. The enzyme catalyses ATP hydrolysis coupled with H+ and K+ exchange across the plasma membrane and is responsible for gastric acid secretion. HGNC lists earlier names including ATPase, H+/K+ exchanging, alpha polypeptide, and the symbol ATP6A. Mouse and rat both have an Atp4a ortholog.
ATP4A is the catalytic subunit of the pump responsible for gastric acid secretion, making it central to studies of stomach acidification.
The E1 to E2 conformational cycle, coupled to transient phosphorylation and ATP hydrolysis, makes ATP4A a model for ion-pumping mechanisms.
ATP4A acts at the apical membrane of parietal cells, where it exchanges luminal K+ for cytoplasmic H+.
As a type IIC P-type ATPase, ATP4A is a useful comparator for studies of cation transport across cell membranes.
ATP4A is the catalytic subunit of the gastric H+/K+ ATPase. It uses ATP to pump H+ ions into the gastric lumen in exchange for K+, acidifying gastric juice to about pH 1. Check the datasheet of any product for its validated reactivity.
ATP4A is also known as ATP6A. Its HGNC name is ATPase H+/K+ transporting subunit alpha, and UniProt calls it potassium-transporting ATPase alpha chain 1. Earlier HGNC names include ATPase, H+/K+ exchanging, alpha polypeptide.
The gastric H+, K+-ATPase is a heterodimer. ATP4A provides the high molecular weight catalytic alpha subunit, paired with a smaller, heavily glycosylated beta subunit. Mouse and rat each have an Atp4a ortholog.
Other P-type ATPases, the gastric pump beta subunit and related ion-transport proteins with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P20648; product specifications from Assay Genie datasheets.