TRPA5 encodes a thermosensitive ankyrin ion channel receptor in a triatomine insect (Source data Fig. S2)

TRPA5 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 TRPA5, a class of ankyrin transient receptor potential channels absent in dipteran genomes, may function as insect heat receptors. In the triatomine bug Rhodnius prolixus (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 in vitrotemperature-induced currents from 53 °C to 68 °C (T0.5= 58.6 °C), 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 TRPA5 as a temperature-activated receptor illustrates the diversity of insect molecular heat detectors.

TRPA5编码锥蝽类昆虫中的热敏性锚蛋白离子通道受体
Marjorie 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. Pierce
作为变温动物，昆虫需要热敏受体以监测环境温度并实现体温调节。本研究表明，TRPA5作为一类在双翅目基因组中缺失的锚蛋白瞬时受体电位（TRP）通道，可作为昆虫的热受体。在作为恰加斯病传播媒介的半翅目昆虫红带锥蝽（*Rhodnius prolixus*）中，通道蛋白RpTRPA5B展现出极高的热敏性，其生物物理特征包括：显著的通道激活焓变（72 kcal/mol）、极高的温度系数（Q₁₀=25），以及体外实验中53℃至68℃范围内的温度诱导电流（半激活温度T₀.₅=58.6℃），该特性与哺乳动物中的伤害性瞬时受体电位香草酸亚型（TRPV）受体相似。单体与四聚体离子通道的结构预测结果显示，其与果蝇dTRPA1存在可靠的结构同源性，但在锚蛋白重复结构域与通道选择性过滤器（潜在的TRP功能调控区域）中存在结构特异性。综上，TRPA5家族成员作为温度激活受体的这一发现，揭示了昆虫分子热感受器的多样性。