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Direct block of hERG potassium channels by the protein kinase C inhibitor bisindolylmaleimide I (GF109203X).
Cardiovasc Res. 2004 Dec 01; 64(3):467-76.CR

Abstract

OBJECTIVE

The human ether-a-go-go-related gene (hERG) encodes the rapid component of the cardiac repolarizing delayed rectifier potassium current, I(Kr). The direct interaction of the commonly used protein kinase C (PKC) inhibitor bisindolylmaleimide I (BIM I) with hERG, KvLQT1/minK, and I(Kr) 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 I(Kr) 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 IC(50) values of 1.0 and 13.2 muM, 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 muM BIM I reduced native I(Kr) 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 I(Kr) currents.

Authors+Show Affiliations

Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany. Dierk_Thomas@med.uni-heidelberg.deNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

15537500

Citation

Thomas, Dierk, et al. "Direct Block of hERG Potassium Channels By the Protein Kinase C Inhibitor Bisindolylmaleimide I (GF109203X)." Cardiovascular Research, vol. 64, no. 3, 2004, pp. 467-76.
Thomas D, Hammerling BC, Wimmer AB, et al. Direct block of hERG potassium channels by the protein kinase C inhibitor bisindolylmaleimide I (GF109203X). Cardiovasc Res. 2004;64(3):467-76.
Thomas, D., Hammerling, B. C., Wimmer, A. B., Wu, K., Ficker, E., Kuryshev, Y. A., Scherer, D., Kiehn, J., Katus, H. A., Schoels, W., & Karle, C. A. (2004). Direct block of hERG potassium channels by the protein kinase C inhibitor bisindolylmaleimide I (GF109203X). Cardiovascular Research, 64(3), 467-76.
Thomas D, et al. Direct Block of hERG Potassium Channels By the Protein Kinase C Inhibitor Bisindolylmaleimide I (GF109203X). Cardiovasc Res. 2004 Dec 1;64(3):467-76. PubMed PMID: 15537500.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Direct block of hERG potassium channels by the protein kinase C inhibitor bisindolylmaleimide I (GF109203X). AU - Thomas,Dierk, AU - Hammerling,Bettina C, AU - Wimmer,Anna-Britt, AU - Wu,Kezhong, AU - Ficker,Eckhard, AU - Kuryshev,Yuri A, AU - Scherer,Daniel, AU - Kiehn,Johann, AU - Katus,Hugo A, AU - Schoels,Wolfgang, AU - Karle,Christoph A, PY - 2004/03/24/received PY - 2004/07/28/revised PY - 2004/07/28/accepted PY - 2004/11/13/pubmed PY - 2005/2/18/medline PY - 2004/11/13/entrez SP - 467 EP - 76 JF - Cardiovascular research JO - Cardiovasc. Res. VL - 64 IS - 3 N2 - OBJECTIVE: The human ether-a-go-go-related gene (hERG) encodes the rapid component of the cardiac repolarizing delayed rectifier potassium current, I(Kr). The direct interaction of the commonly used protein kinase C (PKC) inhibitor bisindolylmaleimide I (BIM I) with hERG, KvLQT1/minK, and I(Kr) 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 I(Kr) 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 IC(50) values of 1.0 and 13.2 muM, 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 muM BIM I reduced native I(Kr) 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 I(Kr) currents. SN - 0008-6363 UR - https://www.unboundmedicine.com/medline/citation/15537500/Direct_block_of_hERG_potassium_channels_by_the_protein_kinase_C_inhibitor_bisindolylmaleimide_I__GF109203X__ L2 - https://academic.oup.com/cardiovascres/article-lookup/doi/10.1016/j.cardiores.2004.07.023 DB - PRIME DP - Unbound Medicine ER -