Voltage-gated sodium (NaV) channels are crucial for action potential initiation and propagation. NaV1.3 plays a significant role in various physiological processes, including neuronal development, hormone secretion, and pain perception. This study presents the structures of human NaV1.3/β1/β2 in complex with bulleyaconitine A (BLA) and the selective antagonist ICA121431. BLA binds near the domain I-II fenestration (site-2 neurotoxin binding site), partially blocking the ion path and expanding pore-lining helices, reducing peak amplitude but increasing open probability. Conversely, ICA121431 binds to the activated domain IV voltage sensor, strengthening the Ile-Phe-Met motif binding, stabilizing the channel in the inactivated state. These findings provide structural details of distinct modulator binding sites and elucidate their mechanisms of action on NaV channels, informing subtype-selective therapeutic development.

Xiaojing Li, Feng Xu, Hao Xu, Shuli Zhang, Yiwei Gao, Hongwei Zhang, Yanli Dong, Yanchun Zheng, Bei Yang, Jianyuan Sun, Xuejun Cai Zhang, Yan Zhao, Daohua Jiang