A molecular filter for the cnidarian stinging response

Abstract

All animals detect and integrate diverse environmental signals to mediate behavior. Cnidarians, including jellyfish and sea anemones, both detect and capture prey using stinging cells called nematocytes which fire a venom-covered barb via an unknown triggering mechanism. Here, we show that nematocytes from Nematostella vectensis use a specialized voltage-gated calcium channel (nCaV) to distinguish salient sensory cues and control the explosive discharge response. Adaptations in nCaV confer unusuallysensitive, voltage-dependent inactivation to inhibit responses to non-prey signals, such as mechanical water turbulence. Prey-derived chemosensory signals are synaptically transmitted to acutely relieve nCaV inactivation, enabling mechanosensitive-triggered predatory attack. These findings reveal a molecular basis for the cnidarian stinging response and highlight general principles by which single proteins integrate diverse signals to elicit discrete animal behaviors.

In vitroandin vivoassays reveal that cations affect nematocyst discharge inMyxobolus cerebralis(Cnidaria: Myxozoa)

“…From similar work in free-living Cnidaria, we hypothesized that nematocysts would exhibit reduced discharge in the presence of the trivalent cation Gd 3+ , as this would interfere with voltage-gated calcium channels involved in the signal transduction step of nematocyst discharge (Gitter et al ., 1994; Salleo et al ., 1994; Weir et al ., 2020). While voltage-gated calcium channels have been identified in nematocysts of free-living Cnidaria, it is not known if they are present in myxozoan nematocysts.…”