Mutation of a conserved proline residue in the β-subunit ectodomain prevents Na+-K+-ATPase oligomerization

K. Geering, P. Jaunin, F. Jaisser, A. M. Merillat, J. D. Horisberger, P. M. Mathews, V. Lemas, D. M. Fambrough, B. C. Rossier

Research output: Contribution to journalArticlepeer-review

Abstract

A highly conserved sequence motif (4 tyrosines and 1 proline: YYPYY) of the Na+-K+-adenosinetriphosphatase (ATPase) β1-subunit ectodomain has been mutagenized to study its possible role in α/β-assembly and sodium pump function. Single as well as double tyrosine mutants (tyrosine to phenylalanine: Y to F) of Xenopus laevis β1-subunits are able to associate with α1-subunits and form functional Na-K pumps at the plasma membrane that are indistinguishable from wild-type α11-Na-K pumps (as assessed by measurements of ouabain binding, 86Rb flux, Na-K pump current, and activation by external potassium). In contrast, a single proline mutation (proline to glycine: P244G) reduced by >90% the proper assembly and function of Na+-K+-ATPase, despite a normal rate of synthesis and core glycosylation. Our data indicate that proline-244 plays a critical role in the proper folding of the β-subunit and its ability to associate efficiently with the α1-subunit in the endoplasmic reticulum.

Original languageEnglish (US)
Pages (from-to)C1169-C1174
JournalAmerican Journal of Physiology - Cell Physiology
Volume265
Issue number4 34-4
StatePublished - Jan 1 1993
Externally publishedYes

Keywords

  • Xenopus laevis
  • functional expression
  • oocyte
  • potassium activation
  • sodium pump
  • sodium-potassium-adenosinetriphosphatase
  • α-subunit

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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