A peptide toxin in ant venom mimics vertebrate EGF-like hormones to cause long-lasting hypersensitivity in mammals.

Abstract

Venoms are excellent model systems for studying evolutionary processes associated with predator-prey interactions. Here, we present the discovery of a peptide toxin, MIITX₂-Mg1a, which is a major component of the venom of the Australian giant red bull ant <i>Myrmecia gulosa</i> and has evolved to mimic, both structurally and functionally, vertebrate epidermal growth factor (EGF) peptide hormones. We show that Mg1a is a potent agonist of the mammalian EGF receptor ErbB1, and that intraplantar injection in mice causes long-lasting hypersensitivity of the injected paw. These data reveal a previously undescribed venom mode of action, highlight a role for ErbB receptors in mammalian pain signaling, and provide an example of molecular mimicry driven by defensive selection pressure.