A nanobody toolkit for the regulation of K2P channel function.

Abstract

Two-Pore Domain (K2P) K+ channels act as important regulators of the membrane potential in both excitable and non-excitable cells. Their dysfunction is implicated in a range of disorders and they represent attractive therapeutic targets. In particular, drugs that modulate TREK K2P channels may be useful for the treatment of certain forms of pain, depression and migraine. In a previous study, we demonstrated that a class of small molecule negatively-charged activators target a common gating mechanism within the selectivity filter of K2P channels to increase channel activity. Although some of these drugs are highly effective, structural conservation within the inner pore and filter gating mechanism of many related K+ channels means that target specificity is difficult to achieve. We now show that a class of biologics based on VHH domains (nanobodies), can achieve far greater selectivity as both activators and inhibitors of TREK-2 channel function and can differentiate between individual members of this family. Structures of TREK-2 in complex with these nanobodies also provides important new insights into their mechanism of action and highlight a new toolkit for the dissection of K2P channel function.