Direct block of hERG potassium channels by the protein kinase C inhibitor bisindolylmaleimide I (GF109203X)
| Autor: | Yuri A. Kuryshev, Dierk Thomas, Daniel Scherer, Bettina C. Hammerling, Eckhard Ficker, Wolfgang Schoels, Hugo A. Katus, Christoph A. Karle, Anna Britt Wimmer, Kezhong Wu, Johann Kiehn |
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| Rok vydání: | 2004 |
| Předmět: |
Indoles
Patch-Clamp Techniques Potassium Channels Physiology Voltage clamp hERG Guinea Pigs Action Potentials Pharmacology Kidney Maleimides Xenopus laevis Physiology (medical) Animals Humans Myocytes Cardiac Cation Transport Proteins Ion channel Protein kinase C Cells Cultured Protein Kinase C Membrane potential biology Dose-Response Relationship Drug Chemistry HEK 293 cells Potassium channel Ether-A-Go-Go Potassium Channels Cell biology Potassium Channels Voltage-Gated Mutation biology.protein Oocytes Drug receptor Female Cardiology and Cardiovascular Medicine |
| Zdroj: | Cardiovascular research. 64(3) |
| ISSN: | 0008-6363 |
| Popis: | Objective: The human ether-a-go-go-related gene (hERG) encodes the rapid component of the cardiac repolarizing delayed rectifier potassium current, IKr. The direct interaction of the commonly used protein kinase C (PKC) inhibitor bisindolylmaleimide I (BIM I) with hERG, KvLQT1/minK, and IKr currents was investigated in this study. Methods: hERG and KvLQT1/minK channels were heterologously expressed in Xenopus laevis oocytes, and currents were measured using the two-microelectrode voltage clamp technique. In addition, hERG currents in stably transfected human embryonic kidney (HEK 293) cells, native IKr currents and action potentials in isolated guinea pig ventricular cardiomyocytes were recorded using whole-cell patch clamp electrophysiology. Results: Bisindolylmaleimide I blocked hERG currents in HEK 293 cells and Xenopus oocytes in a concentration-dependent manner with IC50 values of 1.0 and 13.2 AM, respectively. hERG channels were primarily blocked in the open state in a frequency-independent manner. Analysis of the voltage-dependence of block revealed a reduction of inhibition at positive membrane potentials. BIM I caused a shift of 20.3 mV in the voltage-dependence of inactivation. The point mutations tyrosine 652 alanine (Y652A) and phenylalanine 656 alanine (F656A) attenuated hERG current blockade, indicating that BIM I binds to a common drug receptor within the pore region. KvLQT1/minK currents were not significantly altered by BIM I. Finally, 1 AM BIM I reduced native IKr currents by 69.2% and lead to action potential prolongation. Conclusion: In summary, PKC-independent effects have to be carefully considered when using BIM I as PKC inhibitor in experimental models involving hERG channels and IKr currents. |
| Databáze: | OpenAIRE |
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