Poison frogs resist their own chemical defense

Abstract

Molecular Evolution Poison frogs sequester and store a neurotoxin that protects them from predation. The frogs, however, run the risk of intoxicating themselves. Studying the frog neurotoxin epibatidine, which binds to acetylcholine receptors, Tarvin et al. found a single amino acid substitution. The substitution changes the configuration of the acetylcholine receptor, so that it decreases its sensitivity to the toxin. But acetylcholine signaling is essential for normal life. Expressing poison frog and human receptors in frog eggs revealed that different amino acid substitutions have occurred in different lineages that allow the frog to resist its own toxins while still letting target neurotransmitters function effectively. Science , this issue p. [1261][1] [1]: /lookup/doi/10.1126/science.aan5061