Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support

Characterization of a β Subunit of the Gastric H+/K+ Transporting ATPase

Michael A. Reuben, Linda S. Lasater and George Sachs
Proceedings of the National Academy of Sciences of the United States of America
Vol. 87, No. 17 (Sep., 1990), pp. 6767-6771
Stable URL: http://www.jstor.org/stable/2355381
Page Count: 5
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
If you need an accessible version of this item please contact JSTOR User Support
Characterization of a β Subunit of the Gastric H+/K+ Transporting ATPase
Preview not available

Abstract

The catalytic subunit of the H+/K+-transporting ATPase (EC 3.6.1.3) has 62% identity to the α, or catalytic subunit, of the Na+/K+-transporting ATPase (EC 3.6.1.37); however, a homologous β subunit was unknown until recently. Removal of the carbohydrate from purified hog H+/K+ATPase vesicles reveals a 35-kDa peptide that, when fragmented with protease V8, gives sequences homologous to both β1 and β2 subunits of the Na+/K+-ATPase. cDNA clones for a β subunit of the gastric H+/K+-ATPase were isolated from a rabbit stomach cDNA library by using degenerate 17-mer oligonucleotide probes made to the protease V8-treated peptides. An open reading frame (54-926) encodes a predicted 291-amino acid peptide with Mr = 33,320, which exhibits 31% and 44% homologies to the Na+/K+-ATPase β1 and Na+/K+-ATPase β2 proteins, respectively. A Kyte-Doolittle hydropathy plot predicts a single N-terminal transmembrane domain with a small hydrophobic region near the C terminus. The presumed extracytosolic domain contains seven potential N-linked glycosylation sites and six out of nine cysteines. Northern (RNA) blot analysis of stomach RNA with the rabbit H+/K+-ATPase β probe identifies a single mRNA of 1.3-1.5 kilobases, similar in concentration to the α subunit mRNA. The presence of a defined gastric H+/K+-ATPase β subunit extends the homology between H+/K+-ATPase and the Na+/K+-ATPase subclass of phosphoenzyme transport ATPase and distinguishes them from the monomeric Ca2+ and proton pump subclasses.

Page Thumbnails

  • Thumbnail: Page 
6767
    6767
  • Thumbnail: Page 
6768
    6768
  • Thumbnail: Page 
6769
    6769
  • Thumbnail: Page 
6770
    6770
  • Thumbnail: Page 
6771
    6771