Referenced in: none

Automatically associated channels: Kv2.1 , Nav1.5

Title: Jingzhaotoxin-35, a novel gating-modifier toxin targeting both Nav1.5 and Kv2.1 channels.

Authors: Peng Wei, Changxi Xu, Qiaoqi Wu, Lang Huang, Songping Liang, Chunhua Yuan

Journal, date & volume: Toxicon, 2014 Dec 15 , 92, 90-6

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/25449098

Abstract
Jingzhaotoxin-35 (JZTX-35), a 36-residue polypeptide, was purified from the venom of the Chinese tarantula Chilobrachys jingzhao. JZTX-35 inhibited Nav1.5 and Kv2.1 currents with the IC50 value of 1.07 μM and 3.62 μM, respectively, but showed no significant effect on either Na(+) currents or Ca(2+) currents evoked in hippocampal neurons. It shifted the activation of the Nav1.5 and Kv2.1 channels to more depolarized voltages, and markedly shifted the steady-state inactivation of Nav1.5 currents toward more hyperpolarized potentials. Moreover, JZTX-35 can bind to a close state of Nav1.5 and Kv2.1 channels. These results indicate that JZTX-35 is a new gating modifier toxin. JZTX-35 shares high sequence similarity with Jingzhaotoxins (JZTXs) targeting Nav1.5 or Kv2.1 channels, but they showed different ion channel selectivity. Structure-function analysis in this study would provide important clues for the exploration of ion channel selectivity of JZTXs.