The Scorpion Toxin Tf2 from Tityus fasciolatus Promotes Nav1.3 Opening

PLoS One. 2015 Jun 17;10(6):e0128578. doi: 10.1371/journal.pone.0128578. eCollection 2015.

Abstract

We identified Tf2, the first β-scorpion toxin from the venom of the Brazilian scorpion Tityus fasciolatus. Tf2 is identical to Tb2-II found in Tityus bahiensis. We found that Tf2 selectively activates human (h)Nav1.3, a neuronal voltage-gated sodium (Nav) subtype implicated in epilepsy and nociception. Tf2 shifts hNav1.3 activation voltage to more negative values, thereby opening the channel at resting membrane potentials. Seven other tested mammalian Nav channels (Nav1.1-1.2; Nav1.4-1.8) expressed in Xenopus oocytes are insensitive upon application of 1 μM Tf2. Therefore, the identification of Tf2 represents a unique addition to the repertoire of animal toxins that can be used to investigate Nav channel function.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Humans
  • Insect Proteins / chemistry
  • Insect Proteins / isolation & purification
  • Insect Proteins / pharmacology*
  • Ion Channel Gating / drug effects*
  • Models, Molecular
  • Molecular Sequence Data
  • NAV1.3 Voltage-Gated Sodium Channel / genetics
  • NAV1.3 Voltage-Gated Sodium Channel / metabolism*
  • Oocytes / metabolism
  • Patch-Clamp Techniques
  • Protein Structure, Tertiary
  • Scorpion Venoms / chemistry
  • Scorpion Venoms / isolation & purification
  • Scorpion Venoms / metabolism
  • Scorpion Venoms / pharmacology*
  • Scorpions / metabolism*
  • Sequence Alignment
  • Sodium Channels / genetics
  • Sodium Channels / metabolism*
  • Xenopus / growth & development
  • Xenopus / metabolism

Substances

  • Insect Proteins
  • NAV1.3 Voltage-Gated Sodium Channel
  • SCN3A protein, human
  • Scorpion Venoms
  • Sodium Channels
  • scorpion toxin II, Tityus