Assay technologies for screening ion channel targets.

The sequence of the human genome will soon provide researchers with hundreds of new ion channel genes. To create a successful ion channel drug discovery program, it is necessary to quickly develop reliable and robust high-throughput screening (HTS) assays for those ion channels implicated in important diseases. Ion channels are dynamic proteins, and therefore require assays that 'sense' their various functional states. Competition-binding assays, although successfully used for other target classes, often fail to identify ligands that modulate specific ion channel functions. Cell-based functional assays, therefore, are preferred for HTS of ion channel targets. In this review, we evaluate the various cell-based assays available for ion channels, and discuss future directions for assay improvements.