Coupling of Slack and NaV1.6 sensitizes Slack to quinidine blockade and guides anti-seizure strategy development.

Tian Yuan, Yifan Wang, Yuchen Jin, Hui Yang, Shuai Xu, Heng Zhang, Qian Chen, Na Li, Xinyue Ma, Huifang Song, Chao Peng, Ze Geng, Jie Dong, Guifang Duan, Qi Sun, Yang Yang, Fan Yang, Zhuo Huang

eLife 2024 Jan 30

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Quinidine has been used as an anticonvulsant to treat patients with KCNT1-related epilepsy by targeting gain-of-function KCNT1 pathogenic mutant variants. However, the detailed mechanism underlying quinidine's blockade against KCNT1 (Slack) remains elusive. Here, we report a functional and physical coupling of the voltage-gated sodium channel NaV1.6 and Slack. NaV1.6 binds to and highly sensitizes Slack to quinidine blockade. Homozygous knockout of NaV1.6 reduces the sensitivity of native sodium-activated potassium currents to quinidine blockade. NaV1.6-mediated sensitization requires the involvement of NaV1.6's N- and C-termini binding to Slack's C-terminus and is enhanced by transient sodium influx through NaV1.6. Moreover, disrupting the Slack-NaV1.6 interaction by viral expression of Slack's C-terminus can protect against SlackG269S-induced seizures in mice. These insights about a Slack-NaV1.6 complex challenge the traditional view of 'Slack as an isolated target' for anti-epileptic drug discovery efforts and can guide the development of innovative therapeutic strategies for KCNT1-related epilepsy. © 2023, Yuan, Wang, Jin et al.

Citation

Tian Yuan, Yifan Wang, Yuchen Jin, Hui Yang, Shuai Xu, Heng Zhang, Qian Chen, Na Li, Xinyue Ma, Huifang Song, Chao Peng, Ze Geng, Jie Dong, Guifang Duan, Qi Sun, Yang Yang, Fan Yang, Zhuo Huang. Coupling of Slack and NaV1.6 sensitizes Slack to quinidine blockade and guides anti-seizure strategy development. eLife. 2024 Jan 30;12