Open AccessCoexpression of alpha 1 with putative beta 3 subunits results in functional Na+/K+ pumps in Xenopus oocytes.
Author(s) -
JeanDaniel Horisberger,
Philippe Jaunin,
Peter J. Good,
Bernard C. Rossier,
K. Geering
Publication year - 1991
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.88.19.8397
Subject(s) - xenopus , gene isoform , beta (programming language) , g alpha subunit , protein subunit , alpha (finance) , biology , microbiology and biotechnology , oocyte , biophysics , chemistry , biochemistry , gene , medicine , embryo , construct validity , nursing , computer science , patient satisfaction , programming language
The active Na+/K+ pump is composed of an alpha and a beta subunit. Until now, three putative isoforms of the beta subunit have been identified that share sequence similarity. We have expressed the beta 1 and beta 3 isoforms of Xenopus laevis Na+/K(+)-ATPase in Xenopus oocytes to compare functional properties of the Na+/K+ pump, including either of these two isoforms. Na+/K+ pump current, estimated as K(+)-induced outward current in voltage-clamped oocytes, was doubled by coexpression of alpha 1 subunits with either isoform of the beta subunit compared to expression of alpha 1 subunits alone. The kinetics of activation by external K+ and the voltage dependence of the electrogenic activity of the Na+/K+ pump were similar with both beta isoforms, indicating that both beta 1 and beta 3 isoforms can support expression at the oocyte surface of an active Na+/K+ pump with similar functional properties.