K 2P 2.1 (TREK-1)-activator Complexes Reveal a Cryptic Selectivity Filter Binding Site

Nature. 2017 Jul 20;547(7663):364-368. doi: 10.1038/nature22988. Epub 2017 Jul 10.

Abstract

Polymodal thermo- and mechanosensitive two-pore domain potassium (K2P) channels of the TREK subfamily generate 'leak' currents that regulate neuronal excitability, respond to lipids, temperature and mechanical stretch, and influence pain, temperature perception and anaesthetic responses. These dimeric voltage-gated ion channel (VGIC) superfamily members have a unique topology comprising two pore-forming regions per subunit. In contrast to other potassium channels, K2P channels use a selectivity filter 'C-type' gate as the principal gating site. Despite recent advances, poor pharmacological profiles of K2P channels limit mechanistic and biological studies. Here we describe a class of small-molecule TREK activators that directly stimulate the C-type gate by acting as molecular wedges that restrict interdomain interface movement behind the selectivity filter. Structures of K2P2.1 (also known as TREK-1) alone and with two selective K2P2.1 (TREK-1) and K2P10.1 (TREK-2) activators-an N-aryl-sulfonamide, ML335, and a thiophene-carboxamide, ML402-define a cryptic binding pocket unlike other ion channel small-molecule binding sites and, together with functional studies, identify a cation-π interaction that controls selectivity. Together, our data reveal a druggable K2P site that stabilizes the C-type gate 'leak mode' and provide direct evidence for K2P selectivity filter gating.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arachidonic Acid / chemistry
  • Arachidonic Acid / metabolism
  • Arachidonic Acid / pharmacology
  • Benzamides / chemistry
  • Benzamides / metabolism
  • Benzamides / pharmacology
  • Binding Sites / drug effects
  • HEK293 Cells
  • Humans
  • Ion Channel Gating / drug effects
  • Lipids
  • Mice
  • Models, Molecular
  • Pichia
  • Potassium Channels, Tandem Pore Domain / agonists*
  • Potassium Channels, Tandem Pore Domain / chemistry*
  • Potassium Channels, Tandem Pore Domain / metabolism
  • Protein Conformation / drug effects
  • Sulfonamides / chemistry
  • Sulfonamides / metabolism
  • Sulfonamides / pharmacology
  • Thiophenes / chemistry
  • Thiophenes / metabolism
  • Thiophenes / pharmacology
  • Xenopus laevis

Substances

  • Benzamides
  • KCNK10 protein, human
  • Lipids
  • N-((2,4-dichlorophenyl)methyl)-4-(methanesulfonamido)benzamide
  • N-(2-(4-chloro-2-methylphenoxy)ethyl)thiophene-2-carboxamide
  • Potassium Channels, Tandem Pore Domain
  • Sulfonamides
  • Thiophenes
  • potassium channel protein TREK-1
  • Arachidonic Acid