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Updated: Mar 11, 2026

Mutagenesis and Functional Analysis of Ion Channels Heterologously Expressed in Mammalian Cells
Published on: October 1, 2010
SGK3 Sensitivity of Large-Conductance Ca2+-Activated K+ Channel
Musaab Ahmed1, Myriam Fezai, Florian Lang
1Department of Cardiology, Vascular Medicine and Physiology, University of Tübingen, Tübingen, Germany.
Background/Aims:
Large conductance Ca2+-activated K+ channels (maxi K+ channels or BK channels) are rapidly activated by increase of cytosolic Ca2+ activity. The channels participate in the regulation of diverse functions including neuronal excitation and cell volume. The BK channels may be modified by kinases. Channel regulating kinases include the serum & glucocorticoid inducible kinase 3 (SGK3). The present study explored whether SGK3 modifies the activity of BK channels.
Methods:
cRNA encoding the Ca2+ insensitive BK channel mutant BKM513I+Δ899-903 was injected into Xenopus laevis oocytes without or with additional injection of cRNA encoding wild-type SGK3, constitutively active S419DSGK3, or catalytically inactive K191NSGK3. K+ channel activity was measured utilizing dual electrode voltage clamp.
Results:
BK channel activity in BKM513I+Δ899-903 expressing oocytes was significantly increased by co-expression of SGK3 or active S419DSGK3, but not by coexpression of inactive K191NSGK3.
Conclusion:
SGK3 is a novel positive regulator of BK channels, and thus participates in the regulation of cell volume and excitability.
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