1 research outputs found
Protein Carbonylation of an Amino Acid Residue of the Na/KāATPase Ī±1 Subunit Determines Na/KāATPase Signaling and Sodium Transport in Renal Proximal Tubular Cells
Background We have demonstrated that cardiotonic steroids, such as ouabain, signaling through the Na/KāATPase, regulate sodium reabsorption in the renal proximal tubule. By direct carbonylation modification of the Pro222 residue in the actuator (A) domain of pig Na/KāATPase Ī±1 subunit, reactive oxygen species are required for ouabaināstimulated Na/KāATPase/cāSrc signaling and subsequent regulation of active transepithelial 22Na+ transport. In the present study we sought to determine the functional role of Pro222 carbonylation in Na/KāATPase signaling and sodium handling.
Methods and Results Stable pig Ī±1 knockdown LLCāPK1āoriginated PYā17 cells were rescued by expressing wildātype rat Ī±1 and rat Ī±1 with a single mutation of Pro224 (corresponding to pig Pro222) to Ala. This mutation does not affect ouabaināinduced inhibition of Na/KāATPase activity, but abolishes the effects of ouabain on Na/KāATPase/cāSrc signaling, protein carbonylation, Na/KāATPase endocytosis, and active transepithelial 22Na+ transport.
Conclusions Direct carbonylation modification of Pro224 in the rat Ī±1 subunit determines ouabaināmediated Na/KāATPase signal transduction and subsequent regulation of renal proximal tubule sodium transport