Structure of the human K2P13.1 channel reveals a hydrophilic pore restriction and lipid cofactor site

Nature structural & molecular biology Pub Date : 2025-02-26 DOI:10.1038/s41594-024-01476-3

Shatabdi Roy-Chowdhury, Seil Jang, Fayal Abderemane-Ali, Fiona Naughton, Michael Grabe, Daniel L. Minor

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Abstract

Polyunsaturated fatty acid (PUFA) lipids modulate the neuronal and microglial leak potassium channel K_2P13.1 (THIK1) and other voltage-gated ion channel (VGIC) superfamily members through poorly understood mechanisms. Here we present cryo-electron microscopy structures of human THIK1 and mutants, revealing a unique two-chamber aqueous inner cavity obstructed by a hydrophilic barrier important for gating, the flow restrictor, and a P1–M4 intersubunit interface lipid at a site, the PUFA site, corresponding to the K_2P small-molecule modulator pocket. This overlap, together with functional studies, indicates that PUFA site lipids are THIK1 cofactors. Comparison with a PUFA-responsive VGIC, K_v7.1, reveals a shared modulatory role for the pore domain intersubunit interface, providing a framework for understanding PUFA action on the VGIC superfamily. Our findings reveal the distinct THIK1 architecture, highlight the importance of the P1–M4 interface for K_2P control by natural and synthetic ligands and should aid in the development of THIK subfamily modulators for neuroinflammation and autism.

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