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Functional expression of N‐terminal truncated α‐subunits of Na,K‐ATPase in Xenopus laevis oocytes
Author(s) -
Burgener-Kairuz Pauline,
Horisberger Jean-Daniel,
Geering Käthi,
Rossier Bernard C.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)81231-v
Subject(s) - xenopus , terminal (telecommunication) , microbiology and biotechnology , chemistry , salientia , biology , biochemistry , gene , computer science , telecommunications
N‐terminal deletion mutants of Na,K‐ATPase α 1 isoforms initiating translation at Met 34 (α 1 T 1 ) or at Met 43 (α 1 T 2 ) were expressed in X. laevis oocytes. Compared to β 3 cRNA injected controls, the co‐expression of α 1 wt, α 1 T 1 , α 1 T 2 with β 3 subunits results in a 2‐ to 3‐fold increase of ouabain binding sites, parallelled by a concomitant increase in Na,K‐pump current. The apparent K ½ for potassium activation of the α 1 T 2 /β 3 Na,K‐pumps is significantly higher than that of the α 1 wt/β 3 or α 1 T 1 /β 3 Na,K‐pumps expressed at the cell surface. Total deletion of the lysine‐rich N‐terminal domain thus allows the expression of active Na,K‐pump but with distinct cation transport properties.