TRP channels sense temperatures ranging from noxious cold to noxious heat. Whether specialized TRP thermosensor modules exist and how they control channel pore gating is unknown. We studied purified human TRPA1 (hTRPA1) truncated proteins to gain insight into the temperature gating of hTRPA1. In patch-clamp bilayer recordings, ∆1–688 hTRPA1, without the N-terminal ankyrin repeat domain (N-ARD), was more sensitive to cold and heat, whereas ∆1–854 hTRPA1, also lacking the S1–S4 voltage sensing-like domain (VSLD), gained sensitivity to cold but lost its heat sensitivity. In hTRPA1 intrinsic tryptophan fluorescence studies, cold and heat evoked rearrangement of VSLD and the C-terminus domain distal to the transmembrane pore domain S5–S6 (CTD). In whole-cell electrophysiology experiments, replacement of the CTD located cysteines 1021 and 1025 with alanine modulated hTRPA1 cold responses. It is proposed that hTRPA1 CTD harbors cold and heat sensitive domains allosterically coupled to the S5–S6 pore region and the VSLD, respectively.

TRP 通道感知从有害寒冷到有害热量的温度。是否存在专门的 TRP 热传感器模块以及它们如何控制通道孔门控是未知的。我们研究了纯化的人类 TRPA1 (hTRPA1) 截短蛋白，以深入了解 hTRPA1 的温度门控。在膜片钳双层记录中，没有 N 端锚蛋白重复结构域 (N-ARD) 的 ∆1–688 hTRPA1 对冷和热更敏感，而 ∆1–854 hTRPA1 也缺乏 S1–S4 电压感应-like 结构域 (VSLD)，获得了对冷的敏感性，但失去了对热的敏感性。在 hTRPA1 固有色氨酸荧光研究中，冷和热诱发 VSLD 和跨膜孔结构域 S5-S6 (CTD) 远端的 C 末端结构域的重排。在全细胞电生理实验中，用丙氨酸调节的 hTRPA1 冷反应替换 CTD 定位的半胱氨酸 1021 和 1025。有人提出，hTRPA1 CTD 含有变构耦合到 S5-S6 孔隙区域和 VSLD 的冷热敏感域。