Brevetoxin and Conotoxin Interactions with Single-Domain Voltage-Gated Sodium Channels from a Diatom and Coccolithophore

Marine Drugs

AlisonR. Taylor¹  JulieA. Koester¹  Ping Yates¹ 

[1] Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC 28403, USA;

关键词: phytoplankton;    membrane excitability;    diatom;    coccolithophore;    algal toxin;    brevetoxin;   

DOI  :  10.3390/md19030140

来源: DOAJ

【 摘 要 】

The recently characterized single-domain voltage-gated ion channels from eukaryotic protists (EukCats) provide an array of novel channel proteins upon which to test the pharmacology of both clinically and environmentally relevant marine toxins. Here, we examined the effects of the hydrophilic µ-CTx PIIIA and the lipophilic brevetoxins PbTx-2 and PbTx-3 on heterologously expressed EukCat ion channels from a marine diatom and coccolithophore. Surprisingly, none of the toxins inhibited the peak currents evoked by the two EukCats tested. The lack of homology in the outer pore elements of the channel may disrupt the binding of µ-CTx PIIIA, while major structural differences between mammalian sodium channels and the C-terminal domains of the EukCats may diminish interactions with the brevetoxins. However, all three toxins produced significant negative shifts in the voltage dependence of activation and steady state inactivation, suggesting alternative and state-dependent binding conformations that potentially lead to changes in the excitability of the phytoplankton themselves.

【 授权许可】

Unknown