K2P channel gating mechanisms revealed by structures of TREK-2 and a complex with Prozac.

K2P channel gating mechanisms revealed by structures of TREK-2 and a complex with Prozac.

Science (New York, N.Y.) (2015-03-15)

Yin Yao Dong, Ashley C W Pike, Alexandra Mackenzie, Conor McClenaghan, Prafulla Aryal, Liang Dong, Andrew Quigley, Mariana Grieben, Solenne Goubin, Shubhashish Mukhopadhyay, Gian Filippo Ruda, Michael V Clausen, Lishuang Cao, Paul E Brennan, Nicola A Burgess-Brown, Mark S P Sansom, Stephen J Tucker, Elisabeth P Carpenter

PMID25766236

ABSTRACT

TREK-2 (KCNK10/K2P10), a two-pore domain potassium (K2P) channel, is gated by multiple stimuli such as stretch, fatty acids, and pH and by several drugs. However, the mechanisms that control channel gating are unclear. Here we present crystal structures of the human TREK-2 channel (up to 3.4 angstrom resolution) in two conformations and in complex with norfluoxetine, the active metabolite of fluoxetine (Prozac) and a state-dependent blocker of TREK channels. Norfluoxetine binds within intramembrane fenestrations found in only one of these two conformations. Channel activation by arachidonic acid and mechanical stretch involves conversion between these states through movement of the pore-lining helices. These results provide an explanation for TREK channel mechanosensitivity, regulation by diverse stimuli, and possible off-target effects of the serotonin reuptake inhibitor Prozac.

MATERIALS

Product Number

Brand

Product Description

10931

Sigma-Aldrich

Arachidonic acid, >95.0% (GC)

A3611

Sigma-Aldrich

Arachidonic acid, from non-animal source, ≥98.5% (GC)

F-918

Supelco

Fluoxetine hydrochloride solution, 1.0 mg/mL in methanol (as free base), ampule of 1 mL, certified reference material, Cerilliant^®