An intracellular proton sensor commands lipid- and mechano-gating of the K(+) channel TREK-1.
The 2P domain K(+) channel TREK-1 is widely expres sed in the nervous system. It is opened by a variety of physical and chemical stimuli including membrane stretch, intracellular acidosis and polyunsaturated fatty acids. This activation can be reversed by PKA-mediated phosphorylation. The C-terminal domain of TREK-1 is critical for its polymodal function. We demonstrate that the conversion of a specific glutamate residue (E306) to an alanine in this region locks TREK-1 in the open configuration and abolishes the cAMP/PKA down-modulation. The E306A substitution mimics intracellular acidosis and rescues both lipid- and mechano-sensitivity of a loss-of-function truncated TREK-1 mutant. We conclude that protonation of E306 tunes the TREK-1 mechanical setpoint and thus sets lipid sensitivity.
Honoré
Eric
E
Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, F-06560 Valbonne, France.
Maingret
François
F
Lazdunski
Michel
M
Patel
Amanda Jane
AJ
D000818:Animals; D019556:COS Cells; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D018698:Glutamic Acid / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating / Q000502:physiology*; D008954:Models, Biological; D016297:Mutagenesis, Site-Directed; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D024683:Potassium Channels, Tandem Pore Domain; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D015221:Potassium Channels; D024683:Potassium Channels, Tandem Pore Domain; C103742:potassium channel protein TREK-1; D018698:Glutamic Acid; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases