Beta-theraphotoxin-Cm1b

UniProtKB accession:  P84508

Grouped By:  Matching UniProtKB accession

UniProtKB description:  Inhibits several voltage-gated sodium channels and only one voltage-gated calcium channel (Cav2.2/CACNA1B (IC(50)=1.1 uM) and Nav1.2/SCN2A (IC(50)=3.7-80 nM), Nav1.3/SCN3A (IC(50)=88-5570 nM), Nav1.1/SCN1A (IC(50)=170-407 nM), Nav1.7/SCN9A (IC(50)=95.5-230 nM), Nav1.6/SCN6A (IC(50)=49.9-3990 nM), Nav1.4/SCN4A (IC(50)=113-400 nM or >10 uM), Nav1.5/SCN5A (IC(50)=1524-1634 nM or >10 uM)) (PubMed:16267209, PubMed:28880874, PubMed:29703751). The toxin acts by shifting the voltage dependence of channel activation to more depolarized potentials and by blocking the inward component of the sodium current (PubMed:16267209). It shows moderate affinity for lipid bilayers without cholesterol and high affinity for lipid bilayers containing cholesterol (PubMed:29703751). In vivo, this toxin causes general ataxia, lack of response to stimuli, and semiparalysis (PubMed:16267209). After a few minutes, the mice are unable to stand, and breathing is reduced in rhythm and intensity (PubMed:16267209). Symptoms gradually increase with progressive slowing of breathing and flaccid paralysis; death occurred within 10 to 20 minutes post injection (PubMed:16267209). Animals remain totally flaccid, and no symptoms of excitatory neurotoxicity are observed (PubMed:16267209).