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Molecular determinant of Nav1.8 sodium channel resistance to the venom from the scorpion Leiurus quinquestriatus hebraeus

Authors
Journal
Neuroscience Letters
0304-3940
Publisher
Elsevier
Publication Date
Volume
331
Issue
2
Identifiers
DOI: 10.1016/s0304-3940(02)00860-1
Keywords
  • Leiurus Quinquestriatus Toxin
  • Nav1.8
  • Nav1.4-Serine
  • Leucine
  • Glutamic Acid And Aspargine
  • Tetrodotoxin
  • Sodium Channel

Abstract

Abstract The scorpion venom from Leiurus quinquestriatus (LQTX) alters the kinetics of tetrodotoxin (TTX)-sensitive channels such as the skeletal muscle sodium channel Na v1.4. In this study, we tested the effects of LQTX on the TTX-resistant sodium current generated by Na v1.8 channels in sensory neurons. Na v1.8 current was found to be resistant to LQTX, whereas LQTX slowed inactivation of the current generated by Na v1.4 and induced a persistent current. LQTX has been shown to bind the S3-S4 linker of domain four (D4S3-S4) of rat brain Na v1.2 sodium channels. Sequence analysis shows that the D4S3-S4 linker is longer in Na v1.8 than in Na v1.4 by four amino acids: Serine; Leucine; Glutamic acid; and Aspargine (SLEN). Na v1.4-SLEN, a chimera construct carrying SLEN at the analogous position in the D4S3-S4 linker, was also found to be resistant to LQTX. Therefore, we conclude that the tetrapeptide SLEN at the D4S3-S4 linker region is sufficient to make Na v1.8 resistant to LQTX.

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