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Discovery and Characterization of Novel BK Ca Channel Modulators Using a New Cell‐Based Assay Platform
Author(s) -
Lee Sojung,
Lee ByoungCheol,
Park ChulSeung
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.1021.7
Subject(s) - bk channel , activator (genetics) , chemistry , calcium activated potassium channel , biophysics , mutant , potassium channel , intracellular , membrane potential , hek 293 cells , electrophysiology , sk channel , ion channel , biochemistry , biology , gene , neuroscience , receptor
The large‐conductance calcium‐activated potassium channel (BK Ca channel) is expressed in various tissues and considered as an attractive therapeutic target due to its critical physiological functions. We recently developed a cell‐based assay system utilizing a hyperactive mutant BK Ca channel ( J Biotechnol . 167:41‐6, 2013). Since an additional maneuver to raise intracellular Ca 2+ is not necessary in this assay, the activity of the mutant BK Ca channels can be monitored using fluorescence measurement under physiological membrane voltages. Using the cell‐based assay, we have screened approximately 2,000 compounds of synthetic and natural origins, and identified initial candidate compounds of 13 activators and 12 inhibitors. We then investigated the mechanism of action for a single natural compound using electrophysiological means. This compound potently activated the BK Ca channel from the outside of the cells by shifting the voltage‐dependent activation profile to more negative voltages. In the presence of the compound, the deactivation of macroscopic channel current was dramatically slowed down suggesting that the binding of the activator stabilizes the channel's open conformation. We are currently examining the characteristic of BK Ca channel activator at a single‐channel level. Our findings verify that the newly developed cell‐based assay can be effectively applied for high‐throughput screening of BK Ca channel and help to discover new sets of the channel modulators.