Voltage-gated sodium channel modulation by scorpion alpha-toxins.
Voltage-gated Na(+) channels are integral membrane proteins that function as a gateway for a selective permeation of sodium ions across biological membranes. In this way, they are crucial players for the generation of action potentials in excitable cells. Voltage-gated Na(+) channels are encoded by at least nine genes in mammals. The different isoforms have remarkably similar functional properties, but small changes in function and pharmacology are biologically well-defined, as underscored by mutations that cause several diseases and by modulation of a myriad of compounds, respectively. This review will stress on the modulation of voltage-gated Na(+) channels by scorpion alpha-toxins. Nature has designed these two classes of molecules as if they were predestined to each other: an inevitable 'encounter' between a voltage-gated Na(+) channel isoform and an alpha-toxin from scorpion venom indeed results in a dramatically changed Na(+) current phenotype with clear-cut consequences on electrical excitability and sometimes life or death. This fascinating aspect justifies an overview on scorpion venoms, their alpha-toxins and the Na(+) channel targets they are built for, as well as on the molecular determinants that govern the selectivity and affinity of this 'inseparable duo'.
Bosmans
Frank
F
Laboratory of Toxicology, University of Leuven, O and N 2, Postbus 922, Herestraat 49, 3000 Leuven, Belgium.
Tytgat
Jan
J
D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D008969:Molecular Sequence Data; D012604:Scorpion Venoms / Q000235:genetics* / Q000494:pharmacology*; D016415:Sequence Alignment; D015222:Sodium Channels / Q000187:drug effects*
D012604:Scorpion Venoms; D015222:Sodium Channels