Target of rapamycin signaling inhibits autophagy in sea cucumber Apostichopus japonicus
Target of rapamycin signaling inhibits autophagy in sea cucumber Apostichopus japonicus
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雷帕霉素信号靶标抑制仿刺参自噬
DOI：
10.1016/j.fsi.2020.05.013
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发表时间：
2020
影响因子：
4.7
通讯作者：
Zhao Xiaodong
中科院分区：
文献类型：
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作者：
Shao Yina;Che Zhongjie;Chen Kaiyu;Li Chenghua;Zhao Xiaodong
mTOR介导的自噬是病原体感染哺乳动物的一种特别重要的免疫防御机制。然而，TOR在棘皮动物自噬中的作用在很大程度上是未知的。本研究从仿刺参（Apostichopus）中克隆了一个编码TOR蛋白的cDNA（命名为AjTOR），并对其生物学功能进行了初步研究。AjTOR基因编码2499个氨基酸，具有DUF3385、FAT、FRB、PI3Kc和FATC等结构域，与脊椎动物同源序列高度保守。系统发育分析支持AjTOR属于TOR家族的一个新成员。组织分布分析表明，AjTOR基因在所有组织中均有表达，其中肌肉组织中表达量最高。灿烂弧菌体内感染和体外LPS刺激均可显著下调AjTOR mRNA的表达。更重要的是，透射电子显微镜观察显示，雷帕霉素处理导致体腔细胞中自噬体在3和6 h快速形成，然而，与对照相比，注射mTOR激活剂MHY1485显示出对自噬体形成的抑制作用，这表明阻断AjTOR的表达可以加速自噬信号。我们的研究结果支持AjTOR作为负调节海参autophay。
Autophagy mediated by mTOR pathway is a particularly important immune defense mechanism in the pathogens infected mammals. However, the role of TOR in echinoderm autophagy is largely unknown. Here, a cDNA encoding TOR protein was cloned and characterized from sea cucumber Apostichopus japonicus (designated asAjTOR) and its biological functions were also investigated. TheAjTORgene encoded a peptide of 2499 amino acids with the representative domains of DUF3385, FAT, FRB, PI3Kc, and FATC, which exhibited highly conservation with vertebrate orthologs. Phylogenetic analysis supported that AjTOR belonged to a new member of TOR family. Moreover, tissues distribution analysis indicated thatAjTORwas ubiquitously expressed in all the tested tissues, with the highest transcription in muscle. Vibrio splendidus infectionin vivoand LPS challengein vitrocould both significantly down-regulate the mRNA expression ofAjTOR. What's more, transmission electron microscopy observations showed that rapamycin treatment resulted in rapid formation of autophagosomes in coelomocytes both at 3 and 6 h, however, injection with mTOR activator of MHY1485 showed an inhibitory effect on autophagosomes formation compared to the control, suggesting blocking the expression of AjTOR could accelerates autophagy signals. Our findings supported that AjTOR served as a negative regulator in sea cucumber authophay.