Several members of the FXYD protein family are tissue-specific regulators of Na,K-ATPase that produce distinct effects on its apparent K(+) and Na(+) affinity. Little is known about the interaction sites between the Na,K-ATPase alpha subunit and FXYD proteins that mediate the efficient association and/or the functional effects of FXYD proteins. In this study, we have analyzed the role of the tr...

Development of epidermis creates stratified epithelium with different sets of ion-transporting enzymes in its layers. We have characterized expression of Na,K- and H,K-ATPase α and β subunits and FXYD isoforms in rat skin. Maturation of rat skin from newborn to adult is associated with an increase in FXYD4 and a decrease of Na,K-ATPase α1-isoform, ATP1B4 and FXYD6 transcripts. Na,K-ATPase of ra...

Apart from Na(+),K(+)-ATPase, a second sodium pump, Na(+)-stimulated, K(+)-independent ATPase (Na(+)-ATPase) is expressed in proximal convoluted tubule of the mammalian kidney. The aim of this study was to develop a method of Na(+)-ATPase assay based on the method previously used by us to measure Na(+),K(+)-ATPase activity. The ATPase activity was assayed as the amount of inorganic phosphate li...

Cardiac remodeling occurs after cardiac pressure/volume overload or myocardial injury during the development of heart failure and is a determinant of heart failure. Preventing or reversing remodeling is a goal of heart failure therapy. Human cardiomyocyte Na(+)/K(+)-ATPase has multiple α isoforms (1-3). The expression of the α subunit of the Na(+)/K(+)-ATPase is often altered in hypertrophic an...

Alveolar epithelial cells effect edema clearance by transporting Na(+) and liquid out of the air spaces. Active Na(+) transport by the basolaterally located Na(+)-K(+)-ATPase is an important contributor to lung edema clearance. Because alveoli undergo cyclic stretch in vivo, we investigated the role of cyclic stretch in the regulation of Na(+)-K(+)-ATPase activity in alveolar epithelial cells. ...

We identified five Na+/K+-ATPase alpha-isoforms in rainbow trout and characterized their expression pattern in gills following seawater transfer. Three of these isoforms were closely related to other vertebrate alpha1 isoforms (designated alpha1a, alpha1b and alpha1c), one isoform was closely related to alpha2 isoforms (designated alpha2) and the fifth was closely related to alpha3 isoforms (de...

In our previous studies, we have demonstrated that the Src-coupled α1 Na/K-ATPase works as a receptor for cardiotonic steroids, such as ouabain, to regulate cellular protein kinase cascades. Here, we explore further the structural determinants of the interaction between the α1 Na/K-ATPase and Src and demonstrate that the Src-coupled α1 Na/K-ATPase allows the cell to decode the transmembrane tra...

PURPOSE The Na(+)-/K(+)-dependent ATPase (Na,K-ATPase) expressed in the basolateral membrane of corneal endothelial cells plays an important role in the pump function of the corneal endothelium. The role of insulin in the regulation of Na,K-ATPase activity and pump function in corneal endothelial cells was investigated. METHODS Confluent monolayers of mouse corneal endothelial cells were expo...