Targeting Ion Channels for Drug Discovery: Emerging Challenges for High Throughput Screening Technologies

Book excerpt: Ligand and voltage-gated ion channels are highly regulated protein molecules that cross the cell membrane allowing ion flow from one side of the membrane to the other. They are ubiquitously expressed in human tissues and consist of one of the largest and best understood functional groups of proteins, with more than 400 members spanning nearly 1% of the human genome. They are involved in a variety of fundamental physiological processes, and their malfunction causes numerous diseases. In terms of the challenges faced in the effort to discover specific drugs in ancient and emerging diseases, ion channels are the third-largest class of target proteins after G-protein-coupled receptors (GPCRs) and kinases. 15% of small molecule drug targets have been reported to be voltage- or ligand-gated ion channels, resulting in approximately 150 new drug candidates in preclinical and clinical studies. Of the ion channel targeting drugs found on the market, these were identified more than a decade ago, and many of the current studies are at various stages of scientific approval. Overcoming these challenges has led the field of ion channel drug discovery to transform over the past 15 years through major advancements in genetic target detection, validation, structure-based drug design, and drug modeling of cell-based diseases.