The Na,K-ATPase β2 subunit is expressed in rat brain and copurifies with Na,K-ATPase activity (original) (raw)
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Journal of Biological Chemistry
Genetics, inc.,'Framinghbm, M a s s a c x k t s 01 701 -We have isolated cDNA clones from rat brain and human liver encoding a putative isoform of the Na,K-ATPase , CY subunit. The rat brain cDNA contains an open reading frame of 870 nucleotides coding for a protein of 290 amino acids with a calculated molecular weight of 33,412. The corresponding amino acid sequence shows 98% identity with its human liver counterpart, The proteins encoded by the rat and human cDNAs exhibit a high degree of primary sequence and secondary structure similarity with the rat Na,K-AT-Pase B subunit. We have therefore termed the polypeptides these cDNAs encode a 82 subunit with the previously characterized rat cDNA encoding a B 1 subunit. Analysis of rat tissue RNA reveals that the 82 subunit gene encodes a 3.4-kilobase mRNA which is expressed in a tissue specific fashion distinct from that of rat 61 subunit mRNA. Cell lines derived from the rat central nervous system shown to lack , C Y 1 subunit mRNA sequences were found to express 82 subunit mRNA. These results suggest that different members of the Na,K-ATPase 8 subunit family may have specialized functions. t *
Molecular cloning of rat brain Na,K-ATPase alpha-subunit cDNA
Proceedings of the National Academy of Sciences, 1985
We have isolated a cDNA clone for the rat brain Na,K-ATPase a subunit. A Agtll cDNA expression library constructed from mRNA of 1-and 2-week-old rat brains was screened with an antibody reactive with rat brain Na,K-ATPase. A positive phage clone, ArbS, containing a 1200-basepair cDNA insert expressed a fi-galactosidase-cDNA fusion protein that was reactive by immunoblotting with the Na,K-ATPase antibody. This fusion protein was also reactive in ELISA with a monoclonal antibody directed against the a subunit of the Na,K-ATPase. A 27S mRNA species exhibiting sequence hybridization to the cDNA insert of Xrb5 was identified in rat brain, kidney, and liver, as well as in dog kidney. This 27S mRNA exhibited a tissue-specific pattern of abundance consistent with the relative abundance of Na,K-ATPase polypeptides in vivo: kidney > brain > liver. In a ouabainresistant HeLa cell line, C+, which contains minute chromosomes and at least a 10-fold greater number of sodium pumps
The Journal of biological chemistry, 1989
We have isolated cDNA clones from rat brain and human liver encoding a putative isoform of the Na,K-ATPase beta subunit. The rat brain cDNA contains an open reading frame of 870 nucleotides coding for a protein of 290 amino acids with a calculated molecular weight of 33,412. The corresponding amino acid sequence shows 98% identity with its human liver counterpart. The proteins encoded by the rat and human cDNAs exhibit a high degree of primary sequence and secondary structure similarity with the rat Na,K-ATPase beta subunit. We have therefore termed the polypeptides these cDNAs encode a beta 2 subunit with the previously characterized rat cDNA encoding a beta 1 subunit. Analysis of rat tissue RNA reveals that the beta 2 subunit gene encodes a 3.4-kilobase mRNA which is expressed in a tissue specific fashion distinct from that of rat beta 1 subunit mRNA. Cell lines derived from the rat central nervous system shown to lack beta 1 subunit mRNA sequences were found to express beta 2 sub...
The Journal of Cell Biology
We have characterized cDNAs coding for three Na,K-ATPase tx subunit isoforms from the rat, a species resistant to ouabain. Northern blot and Sl-nuclease mapping analyses revealed that these a subunit mRNAs are expressed in a tissue-specific and developmentally regulated fashion. The mRNA for the al isoform, --~-4.5 kb long, is expressed in all fetal and adult rat tissues examined. The a2 mRNA, also ---4.5 kb long, is expressed predominantly in brain and fetal heart. The ix3 cDNA detected two mRNA species: a ---4.5 kb mRNA present in most tissues and a ---6 kb mRNA, found only in fetal brain, adult brain, heart, and skeletal muscle. The deduced amino acid sequences of these isoforms are highly conserved. However, significant differences in codon usage and patterns of genomic DNA hybridization indicate that the a subunits are encoded by a multigene family. Structural analysis of the a subunits from rat and other species predicts a polytopic protein with seven membranespanning regions. Isoform diversity of the a subunit may provide a biochemical basis for Na,K-ATPase functional diversity.
Journal of Cell Biology, 1987
We have characterized cDNAs coding for three Na,K-ATPase tx subunit isoforms from the rat, a species resistant to ouabain. Northern blot and Sl-nuclease mapping analyses revealed that these a subunit mRNAs are expressed in a tissue-specific and developmentally regulated fashion. The mRNA for the al isoform,-~-4.5 kb long, is expressed in all fetal and adult rat tissues examined. The a2 mRNA, also-4.5 kb long, is expressed predominantly in brain and fetal heart. The ix3 cDNA detected two mRNA species: a-4.5 kb mRNA present in most tissues and a-6 kb mRNA, found only in fetal brain, adult brain, heart, and skeletal muscle. The deduced amino acid sequences of these isoforms are highly conserved. However, significant differences in codon usage and patterns of genomic DNA hybridization indicate that the a subunits are encoded by a multigene family. Structural analysis of the a subunits from rat and other species predicts a polytopic protein with seven membranespanning regions. Isoform diversity of the a subunit may provide a biochemical basis for Na,K-ATPase functional diversity.