Rat-brain Na,K-ATPase beta-chain gene: primary structure, tissue-specific expression, and amplification in ouabain-resistant HeLa C+ cells.

Abstract

We deduced the complete amino acid sequence of the rat brain Na,K-ATPase ,-subunit from cDNA. The rat brain "-subunit exhibits a high degree of primary sequence and secondary structural homology with the human and Torpedo (i-subunit polypeptides. Analysis of rat tissue RNA reveals that the ,B-subunit gene encodes four separate mRNA species which are expressed in a tissue-specific fashion. In ouabain-resistant HeLa C+ cells, ,B-subunit DNA sequences are amplified (-20-fold) and "-subunit mRNAs are overproduced relative to levels in parental HeLa cells. These results suggest that the (-subunit plays an important role in Na,K-ATPase structure-function and in the mechanism underlying cellular resistance to the cardiac glycosides.

Regulation of blastocyst formation

“…The enzyme establishes and maintains the high internal K + and low internal Na + concentrations found in eukaryotic cells (137)(138)(139)(140)(141)(142)(143)(144)(145)(146)(147)(148)(149). The enzyme actively transports 3 Na + out of the cell and 2 K + into the cell for each molecule of hydrolyzed ATP.…”

“…The Na + gradient provides the energy for Na + -coupled transporters that mediate the translocation of ions (H + , Ca 2+ , Cl -, PO 4 -), substrates (glucose and amino acids) and neurotransmitters (136). The catalytic alphasubunit of M r 100 kD is responsible for ion transport (139)(140)(141)(142)(143)(144)(145). The beta-subunit of M r 40-60 kD facilitates the processing and insertion of the alpha-subunit into the plasma membrane (138,145).…”

“…The beta-subunit of M r 40-60 kD facilitates the processing and insertion of the alpha-subunit into the plasma membrane (138,145). In mammals these subunits are encoded by multi-gene families consisting of four alpha subunit genes (alpha1, alpha2, alpha3, alpha 4) and three beta subunit genes (beta 1, beta 2, beta 3), each displaying a distinct temporal and spatial expression pattern (139)(140)(141)(142)(143)(144)(145)(146)(150)(151)(152). The gamma-subunit is a small (8-14 kD) hydrophobic peptide whose function is c urrently under investigation (146,148,150).…”

Advances in Na+,K+‐ATPase studies: from protein to gene and back to protein

“…First, whether heterogeneity of the&subunits exists at the protein level, apart from the heterogeneity of glycosylation. &Subunit mRNAs from different sources (Torpedo [17], sheep, pig, dog and chicken [18,19,22,23], human HeLa cells [20], rat [21,83]) are cloned. In each case only the coding sequence was found.…”

Molecular cloning of the β‐subunit of the Na,K‐ATPase in the brine shrimp, Artemia

“…The enzyme molecule consists of equimolar amounts of the catalytic a-subunit and a glycosylated P-subunit of unknown function. The cDNAs coding for the P-subunit of the Na,K-ATPase have been cloned and sequenced in chicken [5], dog [6], human [7], pig [S], rat [9], sheep [lo], Torpedo [ll], and Xenopus [12].…”