In situ inhibition of vesicle transport and protein processing in the dominant negative Rab1 mutant of Drosophila.
In situ inhibition of vesicle transport and protein processing in the dominant negative Rab1 mutant of Drosophila.
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DOI：
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发表时间：
1997-12
影响因子：
4
通讯作者：
A. Satoh;F. Tokunaga;S. Kawamura;K. Ozaki
中科院分区：
文献类型：
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作者：
A. Satoh;F. Tokunaga;S. Kawamura;K. Ozaki
Rab蛋白在囊泡运输中起重要作用。特别是RAB1被认为参与大多数膜蛋白和分泌蛋白的运输。为了研究RAB1在原位发育或功能细胞中的作用，我们构建了转基因、显性阴性的果蝇RAB1突变体，并检测了突变体光感受器细胞的蛋白转运和细胞和亚细胞结构。在转基因蝇中，突变体RAB1是由Gal4蛋白诱导表达的，而Gal4蛋白的表达是通过对果蝇进行37℃热处理触发的。热诱导后数小时内，粗面内质网（rER）管腔肿胀，高尔基体解体成囊泡团。与细胞结构的这些变化相对应，视紫红质在内质网和高尔基体之间的运输被阻断，这表明未成熟的视紫红质积累了一个大的高甘露糖型低聚糖链。RAB1突变体的长期表达导致光感受性微绒毛的降解和大量肿胀的rer的积累，而在轴突区域未发现明显的变化。这些结果表明，在果蝇光感受器细胞中，RAB1通过介导内质网和高尔基体之间的囊泡运输，有助于维持局部细胞结构。
Rab proteins play an essential role in vesicle transport. In particular, RAB1 is thought to participate in the transport of most membrane and secretory proteins. To investigate the role of RAB1 in developing or functioning cells in situ, we constructed transgenic, dominant-negative Rab1 mutants of Drosophila, and examined the protein transport and cellular and subcellular structures of mutant photoreceptor cells. In the transgenic fly, the expression of mutant RAB1 was induced by Gal4 protein, whose expression was triggered by heat treatment (37 degrees C) of the fly. Within several hours after the heat induction, the lumens of the rough endoplasmic reticulum (rER) became swollen, and Golgi bodies were disassembled into vesicle clusters. Corresponding to these changes in cell structure, rhodopsin transport was blocked between the rER and the Golgi body, as indicated by the accumulation of immature rhodopsin carrying a large high-mannose-type oligosaccharide chain. Long-term expression of mutant RAB1 caused the degradation of photoreceptive microvilli and the accumulation of numerous swollen rERs, whereas no distinct changes were found in the axonal regions. These results indicate that, in Drosophila photoreceptor cells, RAB1 contributes to the maintenance of local cell structure by mediating vesicle transport between the rER and Golgi body.