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Updated: Apr 22, 2026

Voltage-Dependent Potassium Current Recording on H9c2 Cardiomyocytes via the Whole-Cell Patch-Clamp Technique
Published on: November 11, 2022
SPAK and OSR1 sensitivity of voltage-gated K+ channel Kv1.5
Bernat Elvira1, Jamshed Warsi, Carlos Munoz
1Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany.
Abstract:
SPS1-related proline/alanine-rich kinase (SPAK) and oxidative stress-responsive kinase 1 (OSR1) are potent regulators of several transporters and ion channels. The kinases are under regulation of with-no-K(Lys) (WNK) kinases. The present study explored whether SPAK and/or OSR1 modify the expression and/or activity of the voltage-gated K(+) channel Kv1.5, which participates in the regulation of diverse functions including atrial cardiac action potential and tumor cell proliferation. cRNA encoding Kv1.5 was injected into Xenopus oocytes with or without additional injection of cRNA encoding wild-type SPAK, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1, and catalytically inactive (D164A)OSR1. Voltage-gated K(+) channel activity was quantified utilizing dual electrode voltage clamp and Kv1.5 channel protein abundance in the cell membrane utilizing chemiluminescence of Kv1.5 containing an extracellular hemagglutinin epitope (Kv1.5-HA). Kv1.5 activity and Kv1.5-HA protein abundance were significantly decreased by wild-type SPAK and (T233E)SPAK, but not by (T233A)SPAK and (D212A)SPAK. Similarly, Kv1.5 activity and Kv1.5-HA protein abundance were significantly down-regulated by wild-type OSR1 and (T185E)OSR1, but not by (T185A)OSR1 and (D164A)OSR1. Both, SPAK and OSR1 decrease cell membrane Kv1.5 protein abundance and activity.
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