Comprehensive functional analysis of Rab GTPases in Drosophila nephrocytes.
Comprehensive functional analysis of Rab GTPases in Drosophila nephrocytes.
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DOI：
10.1007/s00441-017-2575-2
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发表时间：
2017-06
影响因子：
3.6
通讯作者：
Han Z
中科院分区：
文献类型：
--
作者：
Fu Y;Zhu JY;Zhang F;Richman A;Zhao Z;Han Z
果蝇肾细胞是苍蝇肾脏系统的重要组成部分，与哺乳动物肾脏的足细胞和近端小管细胞具有结构和功能上的同源性。研究肾细胞的生物学过程是了解昆虫肾脏系统的基础。肾细胞在内吞和囊泡运输中高度活跃。RAB GTP酶调节细胞内吞和转运，但肾细胞RAB的具体功能尚不清楚。我们分析了Rab GTPase在果蝇肾细胞中的表达和功能，发现27个果蝇RAB中有11个是正常活动所必需的。RAB 1、5、7、11和35是最重要的。肾细胞特异的Rab5基因沉默消除了所有细胞内的囊泡和肾细胞功能所必需的特殊质膜结构；Rab7沉默显著增加了透明空泡，减少了溶酶体；Rab11沉默显著增加了溶酶体，减少了透明空泡。我们的结果表明，Rab5介导的内吞作用对于维持重要的肾细胞质膜结构是必不可少的，而rab7和11分别介导了导致蛋白质降解和膜循环的另一种下游囊泡运输途径。阐明肾细胞功能的分子途径有可能对人类肾细胞生理学和导致疾病的细胞损伤机制产生重要的见解。有限的治疗选择和高发病率意味着在异常的足细胞和近端小管细胞中发现有希望的治疗靶点是当务之急。果蝇肾细胞正在成为一种有用的体内模型系统，用于分子靶标识别和治疗方法的初步测试。
The Drosophila nephrocyte is a critical component of the fly renal system, and bears structural and functional homology to podocytes and proximal tubule cells of the mammalian kidney. Investigations of nephrocyte cell biological processes are fundamental to understanding the insect renal system. Nephrocytes are highly active in endocytosis and vesicle trafficking. Rab GTPases regulate endocytosis and trafficking, but specific functions of nephrocyte Rabs remain undefined. We analyzed Rab GTPase expression and function in Drosophila nephrocytes and found that 11 out of 27 Drosophila Rabs were required for normal activity. Rabs 1, 5, 7, 11, and 35 were most important. Nephrocyte specific Rab5 gene silencing eliminated all intracellular vesicles and the specialized plasma membrane structures essential for nephrocyte function; Rab7 silencing dramatically increased clear vacuoles and reduced lysosomes; Rab11 silencing increased lysosomes and reduced clear vacuoles. Our results suggest that Rab5 mediates endocytosis that is essential for maintenance of functionally critical nephrocyte plasma membrane structures, and that Rabs 7 and 11 mediate alternative downstream vesicle trafficking pathways leading to protein degradation and membrane recycling, respectively. Elucidating molecular pathways underlying nephrocyte function has the potential to yield important insights into human kidney cell physiology and mechanisms of cell injury that lead to disease. Limited treatment options and high incidence mean that discovering promising therapeutic targets in abnormal podocytes and proximal tubule cells is a priority. The Drosophila nephrocyte is emerging as a useful in vivo model system for molecular target identification and initial testing of therapeutic approaches.