Isolation and cloning of the K+-independent, ouabain-insensitive Na+-ATPase

► K+-independent, ouabain-insensitive Na+-ATPase was purified from enterocytes. ► It is constituted by an α-subunit of 90 kDa and a glycosylated β-subunit of 50 kDa. ► Its corresponding cDNA (atna) was cloned and encodes a protein with 811 amino acids. ► The atna cDNA codes for 6 transmembrane domains and the 9 P-type ATPase motifs. ► Na+- and Na+/K+-ATPase mRNAs seem to be independently transcribed from atp1a1 locus.