Nature:體內TRPA1蛋白質主導果蠅病痛

在最新一期的《自然》雜誌上，布蘭代斯大學國家中心行為基因組學的生物學家Paul Garrity和他的研究團隊報告說，果蠅使用TRPA1在辛辣的芥末醬中區分夏日的溫暖，TRPA1是一種人類相關的蛋白質，是用來控制疼痛和炎症的關鍵。

研究人員使用檢測熱和化學品的方法來研究果蠅的一種蛋白質，可能終有一天會給人類疼痛和控制蚊蟲傳播疾病提供解決方案。

果蠅用與人類共享的鑑定疼痛和炎症的機制來感受在食物中的辛辣化學品

在Garrity團隊的最新研究中發現，果蠅像人類一樣使用TRPA1來感受化學刺激，說明了有害化學感覺的古老起源。在2008年，團隊證明了這種蛋白質在果蠅中的第二個功能：感應溫暖。

柔和的溫暖和討厭的化學物質會觸發截然不同的反應.如何依賴於同一感應器對這兩種反應做出回應呢？研究小組已經發現了這是一個簡單的答案，昆蟲實際上產生兩種形式的TRPA1，每個TRPA1負責各自的任務。

這項新研究的意義是什麼？

這種TRPA1的特殊含義是設計殺蟲劑和陷阱來防止疾病（如瘧疾、登革熱和西尼羅河病毒）的傳播。TRPA1的作用可以解釋吸血昆蟲如蚊子是如何區分有害的化學品從而抵制他們的，人體的溫暖可以吸引蚊子，通過激活其中一種TRPA1，你也許可以阻止蚊子的叮咬，而激活另一種TRPA1可能引誘蚊子進入陷阱。

這些發現也有助於認識人類損壞感覺神經元工作的方式。由於人類TRPA1是一個旨在治療疾病（如哮喘、偏頭痛和慢性疼痛）的藥物靶標，重要的是要了解TRPA1蛋白質是如何運作的。(生物谷 Bioon.com)

Modulation of TRPA1 thermal sensitivity enables sensory discrimination in Drosophila

Kyeongjin Kang,Vincent C. Panzano,Elaine C. Chang,Lina Ni,Alexandra M. Dainis,Adam M. Jenkins,Kimberly Regna,Marc A. T. Muskavitch& Paul A. Garrity

Discriminating among sensory stimuli is critical for animal survival. This discrimination is particularly essential when evaluating whether a stimulus is noxious or innocuous. From insects to humans, transient receptor potential (TRP) channels are key transducers of thermal, chemical and other sensory cues^{1, 2}. Many TRPs are multimodal receptors that respond to diverse stimuli^{1, 2, 3}, but how animals distinguish sensory inputs activating the same TRP is largely unknown. Here we determine how stimuli activating Drosophila TRPA1 are discriminated. Although Drosophila TRPA1 responds to both noxious chemicals⁴and innocuous warming⁵, we find that TRPA1-expressing chemosensory neurons respond to chemicals but not warmth, a specificity conferred by a chemosensory-specific TRPA1 isoform with reduced thermosensitivity compared to the previously described isoform. At the molecular level, this reduction results from a unique region that robustly reduces the channel’s thermosensitivity. Cell-type segregation of TRPA1 activity is critical: when the thermosensory isoform is expressed in chemosensors, flies respond to innocuous warming with regurgitation, a nocifensive response. TRPA1 isoform diversity is conserved in malaria mosquitoes, indicating that similar mechanisms may allow discrimination of host-derived warmth—an attractant—from chemical repellents. These findings indicate that reducing thermosensitivity can be critical for TRP channel functional diversification, facilitating their use in contexts in which thermal sensitivity can be maladaptive.