δ-conotoxin SuVIA suggests an evolutionary link between ancestral predator defence and the origin of fish-hunting behaviour in carnivorous cone snails
Jin, A.-H.; Israel, M.R.; Inserra, M.C.; Smith, J.J.; Lewis, R.J.; Alewood, P.F.; Vetter, I.; Dutertre, S. (2015). δ-conotoxin SuVIA suggests an evolutionary link between ancestral predator defence and the origin of fish-hunting behaviour in carnivorous cone snails. Proc. - Royal Soc., Biol. Sci. 282(1811): 20150817. https://dx.doi.org/10.1098/rspb.2015.0817 In: Proceedings of the Royal Society of London. Series B. The Royal Society: London. ISSN 0962-8452; e-ISSN 1471-2954, more |  |
| Keyword | | | Author keywords | conotoxin; defence; predation; venom; molecular evolution |
| Authors | | Top | - Jin, A.-H.
- Israel, M.R.
- Inserra, M.C.
- Smith, J.J.
| - Lewis, R.J.
- Alewood, P.F.
- Vetter, I., more
- Dutertre, S.
| |
| Abstract | Some venomous cone snails feed on small fishes using an immobilizing combination of synergistic venom peptides that target Kv and Nav channels. As part of this envenomation strategy, δ-conotoxins are potent ichtyotoxins that enhance Nav channel function. δ-Conotoxins belong to an ancient and widely distributed gene superfamily, but any evolutionary link from ancestral worm-eating cone snails to modern piscivorous species has not been elucidated. Here, we report the discovery of SuVIA, a potent vertebrate-active δ-conotoxin characterized from a vermivorous cone snail (Conus suturatus). SuVIA is equipotent at hNaV1.3, hNaV1.4 and hNaV1.6 with EC50s in the low nanomolar range. SuVIA also increased peak hNaV1.7 current by approximately 75% and shifted the voltage-dependence of activation to more hyperpolarized potentials from –15 mV to –25 mV, with little effect on the voltage-dependence of inactivation. Interestingly, the proximal venom gland expression and pain-inducing effect of SuVIA in mammals suggest that δ-conotoxins in vermivorous cone snails play a defensive role against higher order vertebrates. We propose that δ-conotoxins originally evolved in ancestral vermivorous cones to defend against larger predators including fishes have been repurposed to facilitate a shift to piscivorous behaviour, suggesting an unexpected underlying mechanism for this remarkable evolutionary transition. |
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