Proteolytic maturation of Drosophila Neuroligin 3 by tumor necrosis factor alpha-converting enzyme in the nervous system
Proteolytic maturation of Drosophila Neuroligin 3 by tumor necrosis factor alpha-converting enzyme in the nervous system
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神经系统中肿瘤坏死因子 α 转换酶对果蝇 Neuroligin 3 的蛋白水解成熟
DOI：
10.1016/j.bbagen.2017.10.021
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发表时间：
2018
影响因子：
3
通讯作者：
Xie Wei
中科院分区：
文献类型：
--
作者：
Wu Jun;Tao Nana;Tian Yao;Xing Guanglin;Lv Huihui;Han Junhai;Lin Chengqi;Xie Wei
背景自闭症相关神经连接蛋白(NLGS)的功能受其翻译后修饰的调节，如蛋白水解性切割。先前的研究表明，DNlg3在果蝇体内有不同的内源性形式，表明它可能经历了蛋白质降解处理。然而，DNlg3蛋白降解过程的分子机制尚不清楚。方法采用分子克隆、细胞培养、免疫组织化学、Western blotting和遗传学等方法对DNlg3的裂解区域进行定位、鉴定和切割方式。结果肿瘤坏死因子α转换酶在其胞外乙酰胆碱酯酶样区特异性切割DNlg3，产生N末端片段和短膜锚定片段(SDNlg3)。DNlg3是以不依赖于活动的方式结构性地处理的。有趣的是，DNlg3在到达细胞表面之前在高尔基体中被细胞内切割，这是一种独特的切割机制，不同于包括啮齿动物Nlg1在内的膜蛋白的“传统”胞外脱落。遗传学研究表明，sDNlg3对于维持果蝇正常的运动活动是必不可少的。结论我们的研究结果揭示了DNlg3独特的切割机制和DNlg3成熟的神经元特异性作用，DNlg3成熟在运动活动中起着重要的作用。
BackgroundThe functions of autism-associated Neuroligins (Nlgs) are modulated by their post-translational modifications, such as proteolytic cleavage. A previous study has shown that there are different endogenous forms of DNlg3 inDrosophila, indicating it may undergo proteolytic processing. However, the molecular mechanism underlying DNlg3 proteolytic processing is unknown. Here, we report a novel proteolytic mechanism that is essential for DNlg3 maturation and function in the nervous system.MethodsMolecular cloning, cell culture, immunohistochemistry, western blotting and genetic studies were employed to map the DNlg3 cleavage region, identify the protease and characterize the cleavage manner. Behavior analysis, immunohistochemistry and genetic manipulations were employed to study the functions of different DNlg3 forms in the nervous system and neuromuscular junction (NMJs).ResultsTumor necrosis factor α-converting enzyme (TACE) cleaved DNlg3 exclusively at its extracellular acetylcholinesterase-like domain to generate the N-terminal fragment and the short membrane-anchored fragment (sDNlg3). DNlg3 was constitutively processed in an activity-independent manner. Interestingly, DNlg3 was cleaved intracellularly in the Golgi apparatus before it arrived at the cell surface, a unique cleavage mechanism that is distinct from ‘conventional’ ectodomain shedding of membrane proteins, including rodent Nlg1. Genetic studies showed that sDNlg3 was essential for maintaining proper locomotor activity inDrosophila.ConclusionsOur results revealed a unique cleavage mechanism of DNlg3 and a neuron-specific role for DNlg3 maturation which is important in locomotor activity.General significanceOur study provides a new insight into a cleavage mechanism of Nlgs maturation in the nervous system.