How to validate a heteromeric ion channel drug target: Assessing proper expression of concatenated subunits

Abstract

Native subtypes of K+ and other ion channels are often hetero-oligomeric combinations of protein subunits. Drugs that selectively target relevant in vivo heteromers are valuable research tools and potential therapeutics. To recreate heteromeric channels as authentic drug targets, multiple subunits have been covalently tethered by concatemerizing their coding sequences. This perspective examines the linking strategies that have proven successful with many channel types and addresses some less desirable outcomes encountered. We discuss a variety of biochemical, electrophysiological, and pharmacological techniques that can assess whether constructs with concatenated subunits lead to expression of the intended uniform population of channels. Careful controls to ensure that channels are properly assembled can validate heterologously expressed concatemers as promising targets for the discovery of highly selective drugs. © 2008 Sack et al.