Crystal Structure of the Human Two-Pore Domain Potassium Channel K2P1

摘要

Two-pore domain potassium (K~+) channels (K2P channels) control the negative resting potential of eukaryotic cells and regulate cell excitability by conducting K~+ ions across the plasma membrane. Here, we present the 3.4 angstrom resolution crystal structure of a human K2P channel, K2P1 (TWIK-1). Unlike other K~+ channel structures, K2P1 is dimeric. An extracellular cap domain located above the selectivity filter forms an ion pathway in which K~+ ions flow through side portals. Openings within the transmembrane region expose the pore to the lipid bilayer and are filled with electron density attributable to a Iky I chains. An interfacial helix appears structurally poised to affect gating. The structure lays a foundation to further investigate how K2P channels are regulated by diverse stimuli.