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The mechanosensitive two-pore domain (K2P) K+ channels (TREK-1, TREK-2, and TRAAK) are important for mechanical and thermal nociception. However, the mechanisms underlying their gating by membrane stretch remain controversial. Here we use molecular dynamics simulations to examine their behavior in a lipid bilayer. We show that TREK-2 moves from the "down" to "up" conformation in direct response to membrane stretch, and examine the role of the transmembrane pressure profile in this process. Furthermore, we show how state-dependent interactions with lipids affect the movement of TREK-2, and how stretch influences both the inner pore and selectivity filter. Finally, we present functional studies that demonstrate why direct pore block by lipid tails does not represent the principal mechanism of mechanogating. Overall, this study provides a dynamic structural insight into K2P channel mechanosensitivity and illustrates how the structure of a eukaryotic mechanosensitive ion channel responds to changes in forces within the bilayer.

Original publication

DOI

10.1016/j.str.2017.03.006

Type

Journal article

Journal

Structure

Publication Date

02/05/2017

Volume

25

Pages

708 - 718.e2

Keywords

K(+) channel gating, K2P channel, KCNK10, KCNK2, KCNK4, Mechanosensitive, TREK-2, Humans, Ion Channel Gating, Lipid Bilayers, Mechanotransduction, Cellular, Potassium Channels, Tandem Pore Domain