title: The Scorpion Toxin Tf2 from Tityus fasciolatus Promotes Nav1.3 Opening.
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.
authors.affiliation: Departamento de Ciências Fisiológicas, Laboratório de Toxinologia, Universidade de Brasília, Brasília, DF, Brazil.
authors.forename: Thalita S
authors.initials: TS
authors.lastname: Camargos
authors.affiliation: Department of Physiology, Johns Hopkins University-School of Medicine, Baltimore, MD, United States of America; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University-School of Medicine, Baltimore, MD, United States of America.
authors.forename: Frank
authors.initials: F
authors.lastname: Bosmans
authors.affiliation: Departamento de Ciências Fisiológicas, Laboratório de Toxinologia, Universidade de Brasília, Brasília, DF, Brazil.
authors.forename: Solange C
authors.initials: SC
authors.lastname: Rego
authors.affiliation: Departamento de Ciências Fisiológicas, Laboratório de Toxinologia, Universidade de Brasília, Brasília, DF, Brazil.
authors.forename: Caroline B F
authors.initials: CB
authors.lastname: Mourão
authors.affiliation: Departamento de Ciências Fisiológicas, Laboratório de Toxinologia, Universidade de Brasília, Brasília, DF, Brazil.
authors.forename: Elisabeth F
authors.initials: EF
authors.lastname: Schwartz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D015640:Ion Channel Gating / Q000187:drug effects*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D062552:NAV1.3 Voltage-Gated Sodium Channel / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D018408:Patch-Clamp Techniques; D017434:Protein Structure, Tertiary; D012604:Scorpion Venoms / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D012605:Scorpions / Q000378:metabolism*; D016415:Sequence Alignment; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*; D014981:Xenopus / Q000254:growth & development / Q000378:metabolism
chemical_list: D019476:Insect Proteins; D062552:NAV1.3 Voltage-Gated Sodium Channel; C424715:SCN3A protein, human; D012604:Scorpion Venoms; D015222:Sodium Channels; C087005:scorpion toxin II, Tityus