Structure of the human TWIK-2 potassium channel and its inhibition by pimozide

• 成果类型: Article
• 署名作者: Khanra, Nandish K.; Wang, Chongyuan; Delgado, Bryce D.; Long, Stephen B.
• 署名单位: Memorial Sloan Kettering Cancer Center; Cornell University; Weill Cornell Medicine; Chinese Academy of Sciences; Shenzhen Institute of Advanced Technology, CAS; Roche Holding; Roche Holding USA; Genentech
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11965
• DOI: 10.1073/pnas.2425709122
• 发表日期: 2025-05-13
• 关键词: c-type inactivation; cryo-em structure; k+ channel; k-2p channels; intracellular potassium; crystal-structure; selectivity; filter; inflammasome; pharmacology

摘要

The potassium channel TWIK-2 is crucial for ATP-induced activation of the NLRP3 inflammasome in macrophages. The channel is a member of the two-pore domain potassium (K2P) channel superfamily and an emerging therapeutic target to mitigate severe inflammatory injury involving NLRP3 activation. We report the cryo-EM structure human TWIK-2. In comparison to other K2P channels, the structure reveals an unusual up conformation of Tyr111 in the selectivity filter and a resulting SF1-P1 pocket behind the filter. Density for acyl chains is present in fenestrations within the transmembrane region that connects the central cavity of the pore to the lipid membrane. Despite its importance as a drug target, limited pharmacological tools are available for TWIK-2. A previous study suggested that the FDA-approved small molecule pimozide might inhibit TWIK-2. Using reconstituted system, we show that pimozide directly inhibits the channel and we determine a cryo-EM structure of a complex with the drug. Pimozide displaces the acyl chains within the fenestrations and binds below the selectivity filter where it would impede ion permeation. The drug may access its binding site by lateral diffusion in the membrane, suggesting that other hydrophobic small molecules could have utility for inhibiting TWIK-2. The work defines the structure of TWIK-2 and provides a structural foundation for development more specific inhibitors with potential utility as anti-inflammatory drugs.