Synthesis and assembly of functional mammalian Na,K-ATPase in yeast.
The yeast Saccharomyces cerevisiae was investigated as an in vivo protein expression system for mammalian Na,K-ATPase. Unlike animal cells, yeast cells lack endogenous Na,K-ATPase. Expression of high affinity ouabain binding sites, ouabain-sensitive ATPase activity, or ouabain-sensitive p-nitrophenylphosphatase activity in membrane fractions of yeast cells was observed to require the expression of both alpha subunit and beta subunit polypeptides of Na,K-ATPase in the same cell. High affinity ouabain binding sites are also expressed at the cell surface of intact yeast cells containing both the alpha subunit and the beta subunit of Na,K-ATPase. These observations demonstrate that both the alpha subunit and the beta subunit of Na,K-ATPase are required for the expression of functional Na,K-ATPase activity and that yeast cells can correctly assemble this oligomeric membrane protein and transport it to the cell surface.
Department of Physiology and Biophysics, University of Southern California School of Medicine, Los Angeles 90033.
B
B
Horowitz
K A
KA
Eakle
G
G
Scheiner-Bobis
G R
GR
Randolph
C Y
CY
Chen
R A
RA
Hitzeman
R A
RA
Farley
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002462:Cell Membrane / Q000201:enzymology; D004247:DNA / Q000235:genetics; D004285:Dogs; D015870:Gene Expression; D007668:Kidney / Q000201:enzymology; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010042:Ouabain / Q000378:metabolism / Q000494:pharmacology; D010957:Plasmids; D012313:RNA / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D012756:Sheep; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D014170:Transformation, Genetic
D046911:Macromolecular Substances; D010042:Ouabain; D012313:RNA; D004247:DNA; D000254:Sodium-Potassium-Exchanging ATPase