Characterization of a tyramine receptor type 2 from hemocytes of rice stem borer, Chilo suppressalis
Characterization of a tyramine receptor type 2 from hemocytes of rice stem borer, Chilo suppressalis
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水稻二化螟血细胞 2 型酪胺受体的表征
DOI：
10.1016/j.jinsphys.2015.03.004
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发表时间：
2015
影响因子：
2.2
通讯作者：
Ye Gong-Yin
中科院分区：
文献类型：
--
作者：
Wu Shun-Fan;Xu Gang;Ye Gong-Yin
钙在许多细胞类型中充当第二信使，包括昆虫血细胞。细胞内钙水平在先天性和适应性免疫信号传导中具有明确的作用。生物胺如章鱼胺（octopamine，OA）、酪胺（tyramine，TA）、多巴胺（dopamine，DA）和5-羟色胺（serotonin，5-HT）等通过激活G蛋白偶联受体（G-protein-coupled receptor，GPCRs）在昆虫体内发挥重要的生理作用。OA和5-HT已被证明可以介导昆虫血细胞对感染和入侵的免疫反应。在这里，我们发现TA增加血细胞蔓延的水稻二化螟，二化螟。此外，我们还从C. suppressalis，即，CsTA 2，与无脊椎动物酪胺受体家族成员具有高度序列相似性。CsTA 2受体在人胚肾（HEK）293细胞中稳定表达，并检测了其配体反应。用TA激活受体可诱导细胞内Ca 2+浓度（[Ca 2 +]i）呈剂量依赖性增加，EC 50值为18.7 ± 5.3 nM，而OA、DA、5-HT和其他潜在激动剂则无此反应。mRNA存在于各种组织中，包括神经索、血细胞、脂肪体、中肠、马氏管和幼虫期的表皮。Western blot和免疫组化结果显示，CsTA 2在血细胞上呈阳性表达。TA还能诱导C. suppressalis.
Calcium acts as a second messenger in many cell types, including insect hemocytes. Intracellular calcium level has a definite role in innate and adaptive immune signaling. Biogenic amines such as octopamine (OA), tyramine (TA), dopamine (DA) and serotonin (5-HT) play various important physiological roles in insects by activating distinct G-protein-coupled receptors (GPCRs) that share a putative seven transmembrane domain structure. OA and 5-HT have been shown that can mediate insect hemocytic immune reactions to infections and invasions. Here, we showed that TA increase hemocyte spreading in the rice stem borer,Chilo suppressalis. Furthermore, we cloned a cDNA encoding a tyramine receptor type 2 from the hemocytes in theC. suppressalis, viz.,CsTA2, which shares high sequence similarity to members of the invertebrate tyramine receptor family. The CsTA2 receptor was stably expressed in human embryonic kidney (HEK) 293 cells, and its ligand response has been examined. Receptor activation with TA induced a dose-dependent increase in intracellular Ca2+concentration ([Ca2+]i) in cells, with an EC50value of 18.7 ± 5.3 nM, whereas OA, DA, 5-HT and other potential agonists did not have this response. The mRNA is present in various tissues including nerve cord, hemocytes, fat body, midgut, Malpighian tubules, and epidermis in the larval stage. Western blot analysis and immunohistochemistry assay displayed that CsTA2 was detected and presented on hemocytes. We also showed that TA induced Ca2+release from the hemocytes ofC. suppressalis.