A splice variant of the Drosophila vesicular monoamine transporter contains a conserved trafficking domain and functions in the storage of dopamine, serotonin, and octopamine
A splice variant of the Drosophila vesicular monoamine transporter contains a conserved trafficking domain and functions in the storage of dopamine, serotonin, and octopamine
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DOI：
10.1002/neu.20146
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发表时间：
2005-09-05
期刊：
影响因子：
--
通讯作者：
Krantz, DE
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文献类型：
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作者：
Greer, CL;Grygoruk, A;Krantz, DE
囊泡单胺转运蛋白 (VMAT) 介导多巴胺 (DA)、血清素 (5HT) 和其他单胺转运至分泌囊泡。哺乳动物 VMAT 和相关的囊泡乙酰胆碱转运蛋白 (VAChT) 的调节被认为涉及膜运输，但其机制仍不清楚。为了促进囊泡转运蛋白功能和调节的遗传分析，我们克隆了囊泡单胺转运蛋白（dVMAT）的果蝇同源物。我们鉴定了两种 mRNA 剪接变体（DVMAT-A 和 B），其 C 末端不同，C 末端负责哺乳动物 VMAT 和 VAChT 的内吞作用。 DVMAT-A 包含在哺乳动物中保守的运输基序，但在秀丽隐杆线虫中不保守，内化分析表明 DVMAT-A C 末端参与内吞作用。 DVMAT-B 包含一个不同的 C 端结构域，从细胞表面内化的效率较低。使用体外转运测定，我们表明 DVMAT-A 识别 DA、5HT、章鱼胺、酪胺和组胺作为底物，并且与哺乳动物 VMAT 同系物类似，被药物利血平和环境毒素 2,2,4,5,6-五氯联苯和七氯抑制。我们开发了一种针对 DVMAT-A 的特异性抗血清，并发现它定位于神经肌肉接头处的多巴胺能和血清素能神经元以及章鱼能 11 型末端。令人惊讶的是，DVMAT-A 在 11 型末端与果蝇囊泡谷氨酸转运蛋白共表达。我们的数据表明，DVMAT-A 在体内充当 DA、5HT 和章鱼胺的囊泡转运蛋白，并将为转运蛋白运输和调节的研究提供强大的无脊椎动物模型。 (c) 2005 年 Wiley 期刊公司。
Vesicular monoamine transporters (VMATs) mediate the transport of dopamine (DA), serotonin (5HT), and other monoamines into secretory vesicles. The regulation of mammalian VMAT and the related vesicular acetylcholine transporter (VAChT) has been proposed to involve membrane trafficking, but the mechanisms remain unclear. To facilitate a genetic analysis of vesicular transporter function and regulation, we have cloned the Drosophila homolog of the vesicular monoamine transporter (dVMAT). We identify two mRNA splice variants (DVMAT-A and B) that differ at their C-terminus, the domain responsible for endocytosis of mammalian VMAT and VAChT. DVMAT-A contains trafficking motifs conserved in mammals but not C. elegans, and internalization assays indicate that the DVMAT-A C-terminus is involved in endocytosis. DVMAT-B contains a divergent C-terminal domain and is less efficiently internalized from the cell surface. Using in vitro transport assays, we show that DVMAT-A recognizes DA, 5HT, octopamine, tyramine, and histamine as substrates, and similar to mammalian VMAT homologs, is inhibited by the drug reserpine and the environmental toxins 2,2,4,5,6-penta-chlorobiphenyl and heptachlor. We have developed a specific antiserum to DVMAT-A, and find that it localizes to dopaminergic and serotonergic neurons as well as octopa-minergic, type 11 terminals at the neuromuscular junction. Surprisingly, DVMAT-A is co-expressed at type 11 terminals with the Drosophila vesicular glutamate transporter. Our data suggest that DVMAT-A functions as a vesicular transporter for DA, 5HT, and octopamine in vivo, and will provide a powerful invertebrate model for the study of transporter trafficking and regulation. (c) 2005 Wiley Periodicals, Inc.