Functional expression of N‐terminal truncated α‐subunits of Na,K‐ATPase in Xenopus laevis oocytes

FEBS Letters

Geering, Käthi¹  Burgener-Kairuz, Pauline¹  Rossier, Bernard C.¹  Horisberger, Jean-Daniel¹ 

[1] Institut de Pharmacologie et de Toxicologie, Université de Lausanne, Bugnon 27, CH-1005 Lausanne, Switzerland

关键词: Na;    K-pump;    Ouabain binding;    Potassium activation;    α1 Isoform;    β3 Isoform;   

DOI  :  10.1016/0014-5793(91)81231-V

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

N-terminal deletion mutants of Na,K-ATPase α₁ isoforms initiating translation at Met³⁴ (α₁T₁) or at Met⁴³ (α₁T₂) were expressed in X. laevis oocytes. Compared to β₃ cRNA injected controls, the co-expression of α₁wt, α₁T₁, α₁T₂ with β₃ 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 α₁T₂/β₃ Na,K-pumps is significantly higher than that of the α₁wt/β₃ or α₁T₁/β₃ 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.

【 授权许可】

Unknown