Assembly of the alpha-subunit of Torpedo californica Na+/K(+)-ATPase with its pre-existing beta-subunit in Xenopus oocytes.
The alpha- and beta-subunits of Torpedo californica Na+/K(+)-ATPase were expressed in turn in single oocytes by alternately microinjecting the specific mRNAs for the alpha- and beta-subunits. The mRNA first injected was degraded prior to the injection of the second mRNA by injecting the antisense oligonucleotide specific for the first mRNA. The pre-existing beta-subunit, which had been synthesized by injecting mRNA for the beta-subunit, could assemble with the alpha-subunit expressed later in the single oocytes and the resulting alpha beta complex acquired both ouabain-binding and Na+/K(+)-ATPase activities. On the other hand, formation of the alpha beta complex was not detected when the alpha-subunit was expressed first, followed by the beta-subunit. These data suggest that the beta-subunit acts as a receptor or a stabilizer for the alpha-subunit upon the biogenesis of Na+/K(+)-ATPase.
Noguchi
S
S
Department of Biology and Biochemistry, University of Occupational and Environmental Health, Kitakyushu, Japan.
Higashi
K
K
Kawamura
M
M
D000818:Animals; D001483:Base Sequence; D002462:Cell Membrane / Q000201:enzymology; D005260:Female; D015870:Gene Expression; D007163:Immunosorbent Techniques; D007700:Kinetics; D046911:Macromolecular Substances; D008845:Microinjections; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000494:pharmacology; D016376:Oligonucleotides, Antisense; D009865:Oocytes / Q000201:enzymology*; D010042:Ouabain / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000096:biosynthesis* / Q000235:genetics; D014101:Torpedo / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014982:Xenopus laevis
D046911:Macromolecular Substances; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase