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Epidermal growth factor receptor tyrosine kinase regulates the human inward rectifier potassium K IR 2.3 channel, stably expressed in HEK 293 cells
Author(s) -
Zhang DeYong,
Zhang YanHui,
Sun HaiYing,
Lau ChuPak,
Li GuiRong
Publication year - 2011
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.2011.01424.x
Subject(s) - hek 293 cells , inward rectifier potassium ion channel , potassium channel , microbiology and biotechnology , tyrosine kinase , receptor , receptor tyrosine kinase , biology , chemistry , signal transduction , ion channel , biochemistry , endocrinology
BACKGROUND AND PURPOSE The detailed molecular modulation of inward rectifier potassium channels (including the K IR 2.3 channel) is not fully understood. The present study was designed to determine whether human K IR 2.3 (K IR 2.3) channels were regulated by protein tyrosine kinases (PTKs). EXPERIMENTAL APPROACH Whole‐cell patch voltage‐clamp, immunoprecipitation, Western blot analysis and site‐directed mutagenesis were employed to determine the potential PTK phosphorylation of Kir2.3 current in HEK 293 cells stably expressing Kir2.3 gene. KEY RESULTS The broad‐spectrum PTK inhibitor genistein (10 µM) and the selective epidermal growth factor (EGF) kinase inhibitor AG556 (10 µM) reversibly decreased K IR 2.3 current and the effect was reversed by the protein tyrosine phosphatase inhibitor, orthovanadate (1 mM). Although EGF (100 ng·mL −1 ) and orthovanadate enhanced K IR 2.3 current, this effect was antagonized by AG556. However, the Src‐family tyrosine kinase inhibitor PP2 (10 µM) did not inhibit K IR 2.3 current. Tyrosine phosphorylation of K IR 2.3 channels was decreased by genistein or AG556, and was increased by EGF or orthovanadate. The decrease of tyrosine phosphorylation of K IR 2.3 channels by genistein or AG556 was reversed by orthovanadate or EGF. Interestingly, the response of K IR 2.3 channels to EGF or AG556 was lost in the K IR 2.3 Y234A mutant channel. CONCLUSION AND IMPLICATIONS These results demonstrate that the EGF receptor tyrosine kinase up‐regulates the K IR 2.3 channel via phosphorylation of the Y234 residue of the WT protein. This effect may be involved in the endogenous regulation of cellular electrical activity.