What are ion channels? And why are so many people excited about them at the moment? In a nutshell, ion channels are fundamental to cellular existence. They are present in the membranes of almost all living cells — from simple bacteria to highly specialized neurons — and are essential for important physiological processes such as sensory transduction, action-potential generation and muscle contraction, to name just a few. Indeed, when their function goes awry, there can be serious consequences, including life-threatening disease.
Ion channels are proteins that allow the passage of charged ions through hydrophobic membranes. But they are not simple holes; ion channels are sophisticated machines that can conduct ions with exquisite specificity, at speeds close to the limit of diffusion, under very tight regulation. And it is these processes, which until recently have remained largely inaccessible except to some inspired electrophysiological experimentation, that are now being exposed in all their glory by pioneering high-resolution structural studies.
Have these structural insights helped us to derive new treatments for debilitating conditions such as epilepsy, diabetes and cystic fibrosis? Not yet — it is early days for rational drug design — but there are high hopes, particularly as many successful drugs already target ion channels. What is also clear is the extent to which research on disease genes has contributed to our understanding of the normal physiological roles that ion channels have and their underlying mechanisms — mechanisms that will continue to fascinate and perplex ‘channelologists’ for years to come.
We are most grateful to the many people who contributed to this Insight, whether by writing, advising or generating the stimulating data discussed in the following pages.