Inhibition of T-type voltage-gated calcium channels by a new scorpion toxin.
The biophysical properties of T-type voltage-gated calcium channels are well suited to pacemaking and to supporting calcium flux near the resting membrane potential in both excitable and non-excitable cells. We have identified a new scorpion toxin (kurtoxin) that binds to the alpha 1G T-type calcium channel with high affinity and inhibits the channel by modifying voltage-dependent gating. This toxin distinguishes between alpha 1G T-type calcium channels and other types of voltage-gated calcium channels, including alpha 1A, alpha 1B, alpha 1C and alpha 1E. Like the other alpha-scorpion toxins to which it is related, kurtoxin also interacts with voltage-gated sodium channels and slows their inactivation. Kurtoxin will facilitate characterization of the subunit composition of T-type calcium channels and help determine their involvement in electrical and biochemical signaling.
Chuang
R S
RS
Molecular Physiology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA.
Jaffe
H
H
Cribbs
L
L
Perez-Reyes
E
E
Swartz
K J
KJ
D000818:Animals; D001667:Binding, Competitive / Q000502:physiology; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism; D020747:Calcium Channels, T-Type; D004594:Electrophysiology; D005260:Female; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D009498:Neurotoxins / Q000378:metabolism / Q000494:pharmacology*; D009865:Oocytes / Q000378:metabolism; D012604:Scorpion Venoms / Q000378:metabolism / Q000494:pharmacology*; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism; D014982:Xenopus laevis
D015220:Calcium Channels; D020747:Calcium Channels, T-Type; D009498:Neurotoxins; D012604:Scorpion Venoms; D015222:Sodium Channels; C118444:kurtoxin