TRAAK is a mammalian neuronal mechano-gated K+ channel.
The novel structural class of mammalian channels with four transmembrane segments and two pore regions comprise background K+ channels (TWIK-1, TREK-1, TRAAK, TASK, and TASK-2) with unique physiological functions (1-6). Unlike its counterparts, TRAAK is only expressed in neuronal tissues, including brain, spinal cord, and retina (1). This report shows that TRAAK, which was known to be activated by arachidonic acid (3), is also opened by membrane stretch. Mechanical activation of TRAAK is induced by a convex curvature of the plasma membrane and can be mimicked by the amphipathic membrane crenator trinitrophenol. Cytoskeletal elements are negative tonic regulators of TRAAK. Membrane depolarization and membrane crenation synergize with stretch-induced channel opening. Finally, TRAAK is reversibly blocked by micromolar concentrations of gadolinium, a well known blocker of stretch-activated channels. Mechanical activation of TRAAK in the central nervous system may play an important role during growth cone motility and neurite elongation.
Maingret
F
F
Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UPR 411, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France.
Fosset
M
M
Lesage
F
F
Lazdunski
M
M
Honoré
E
E
D000818:Animals; D019556:COS Cells; D003599:Cytoskeleton / Q000502:physiology; D004594:Electrophysiology; D005682:Gadolinium / Q000494:pharmacology; D015640:Ion Channel Gating / Q000502:physiology*; D008465:Mechanoreceptors / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D014162:Transfection
D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D005682:Gadolinium