Functional expression of N-terminal truncated alpha-subunits of Na,K-ATPase in Xenopus laevis oocytes

FEBS Lett. 1991 Sep 23;290(1-2):83-6. doi: 10.1016/0014-5793(91)81231-v.

Abstract

N-terminal deletion mutants of Na,K-ATPase alpha 1 isoforms initiating translation at Met34 (alpha 1T1) or at Met43 (alpha 1T2) were expressed in X. laevis oocytes. Compared to beta 3 cRNA injected controls, the co-expression of alpha 1wt, alpha 1T1, alpha 1T2 with beta 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 K1/2 for potassium activation of the alpha 1T2/beta 3 Na,K-pumps is significantly higher than that of the alpha 1wt/beta 3 or alpha 1T1/beta 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Chromosome Deletion
  • DNA Mutational Analysis
  • Molecular Sequence Data
  • Oligonucleotides / chemistry
  • Oocytes
  • Potassium / metabolism
  • Recombinant Proteins
  • Sodium-Potassium-Exchanging ATPase* / genetics
  • Sodium-Potassium-Exchanging ATPase* / metabolism*
  • Structure-Activity Relationship
  • Xenopus laevis / genetics
  • Xenopus laevis / metabolism

Substances

  • Oligonucleotides
  • Recombinant Proteins
  • Sodium-Potassium-Exchanging ATPase
  • Potassium