The H+,K+-ATPase has been postulated to be the enzyme responsible for H+ secretion by the parietal cell. Omeprazole has been shown to be an inhibitor of acid secretion in vivo, but also in in vitro test models for acid secretion, including partly purified H+,K+-ATPase, the inhibitory action of omeprazole has been demonstrated (Wallmark, B., Jaresten, B. M., Larsson, H., Ryberg, B., Brändström, ...

Stomata in the plant epidermis open in response to blue light and affect photosynthesis and plant growth by regulating CO2 uptake and transpiration. In stomatal guard cells under blue light, plasma membrane H+-ATPase is phosphorylated and activated via blue light-receptor phototropins and a signaling mediator BLUS1, and H+-ATPase activation drives stomatal opening. However, details of the signa...

H(+) transport in the collecting duct is regulated by exocytic insertion of H(+)-ATPase-laden vesicles into the apical membrane. The soluble N-ethylmaleimide-sensitive fusion protein attachment protein (SNAP) receptor (SNARE) proteins are critical for exocytosis. Syntaxin 1A contains three main domains, SNARE N, H3, and carboxy-terminal transmembrane domain. Several syntaxin isoforms form SNARE...

The baculovirus expression system is suitable for functional expression of gastric H+,K(+)-ATPase. Expression of functional H+,K(+)-ATPase in Sf9 cells is accompanied by synthesis of large amounts of non-functional subunits. When H+,K(+)-ATPase is synthesised in the presence of 150-250 mM ethanol in the culture medium, two to threefold higher levels of functional H+,K(+)-ATPase are produced due...

Cardiac steroids inhibit Na,K-ATPase and the related non-gastric H,K-ATPase, while they do not interact with gastric H,K-ATPase. Introducing an arginine, the residue present in the gastric H,K-ATPase, in the second extracellular loop at the corresponding position 334 in the human non-gastric H,K-ATPase (D334R mutation) rendered it completely resistant to 2mM ouabain. The corresponding mutation ...

A pharmacological screen identified the H+ and K+ ATPase transporter as obligatory for normal orientation of the left-right body axis in Xenopus. Maternal H+/K+-ATPase mRNA is symmetrically expressed in the 1-cell Xenopus embryo but becomes localized during the first two cell divisions, demonstrating that asymmetry is generated within two hours postfertilization. Although H+/K+-ATPase subunit m...

An anion-sensitive H(+)-translocating ATPase was identified in membrane vesicles isolated from mature green tomato (Lycopersicon esculentum) fruit. The H(+)-ATPase was associated with a low density membrane population having a peak density of 1.11 grams per cubic centimeter, and its activity was inhibited by NO(3) (-), N,N'-dicyclohexylcarbodiimide and diethylstilbestrol but not by vanadate, az...

The vacuolar H(+)-translocating ATPase (H(+)-ATPase), originally reported to consist of three major subunits, has been further purified from oat roots (Avena sativa var Lang) to determine the complete subunit composition. Triton-solubilized ATPase activity was purified by gel filtration on Sephacryl S400 and ion-exchange chromatography (Q-Sepharose). ATP hydrolysis activity of purified preparat...