Source data Fig. 1

<i>TRPA5</i><i> </i>encodes a thermosensitive ankyrin ion channel receptor in a triatomine insectMarjorie A. Liénard, David Baez-Nieto, Cheng-Chia Tsai, Wendy A. Valencia-Montoya, Balder Werin, Urban Johanson, Jean-Marc Lassance, Jen Q. Pan, Nanfang Yu, Naomi E. PierceAs ectotherms, insects need heat-sensitive receptors to monitor environmental temperatures and facilitate thermoregulation. We show that <i>TRPA5,</i><i> </i>a class of ankyrin transient receptor potential channels absent in dipteran genomes, may function as insect heat receptors. In the triatomine bug <i>Rhodnius prolixus</i><i> </i>(Order: Hemiptera), a vector of Chagas disease, the channel RpTRPA5B displays a uniquely high thermosensitivity, with biophysical determinants including a large channel activation enthalpy change (72 kcal/mol), a high temperature coefficient (Q₁₀ = 25), and <i>in vitro</i> temperature-induced currents<i> </i>from 53 °C to 68 °C (T_0.5= 58.6 °C)<i>,</i> similar to noxious TRPV receptors in mammals. Monomeric and tetrameric ion channel structure predictions show reliable parallels with fruit fly dTRPA1, with structural uniqueness in ankyrin repeat domains and the channel selectivity filter, potential TRP functional modulator regions. Overall, the finding of a member of <i>TRPA5</i> as a temperature-activated receptor illustrates the diversity of insect molecular heat detectors.