The Scorpion Toxin Tf2 from Tityus fasciolatus Promotes Nav1.3 Opening |
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| Authors: | Thalita S. Camargos Frank Bosmans Solange C. Rego Caroline B. F. Mour?o Elisabeth F. Schwartz |
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| Affiliation: | 1. Departamento de Ciências Fisiológicas, Laboratório de Toxinologia, Universidade de Brasília, Brasília, DF, Brazil.; 2. Department of Physiology, Johns Hopkins University—School of Medicine, Baltimore, MD, United States of America.; 3. Solomon H. Snyder Department of Neuroscience, Johns Hopkins University—School of Medicine, Baltimore, MD, United States of America.; The Hebrew University Medical School, ISRAEL, |
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| 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. |
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