Essential function of Drosophila Sec6 in apical exocytosis of epithelial photoreceptor cells.
Essential function of Drosophila Sec6 in apical exocytosis of epithelial photoreceptor cells.
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DOI：
10.1083/jcb.200410081
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发表时间：
2005-05-23
影响因子：
7.8
通讯作者：
Tepass, Ulrich
中科院分区：
文献类型：
--
作者：
Beronja, Slobodan;Laprise, Patrick;Papoulas, Ophelia;Pellikka, Milena;Sisson, John;Tepass, Ulrich
极化胞吐作用在发育和细胞分化中起主要作用，但在动物细胞中针对特定膜域的胞吐作用机制仍然知之甚少。我们研究了果蝇Sec6，这是一种胞囊复合体的成分，被认为可以将分泌囊泡连接到特定的质膜位置。Sec6突变会导致细胞死亡，并扰乱质膜生长。在发育中的光感受器细胞(PRCs)中，Sec6而不是Sec5或Sec8在贴壁连接处积聚。在晚期，Sec6、Sec5和Sec8共同定位于横纹层，横纹层是顶膜的感光亚区。Sec6功能降低的PRCs积聚分泌小泡，不能将蛋白质转运到横纹肌，但显示蛋白质正常定位于顶端茎膜和基侧膜。此外，我们发现Rab11与Sec5形成了一个复合体，Sec5与Sec6相互作用，这表明该外囊是一种Rab11效应器，促进了蛋白质在果蝇PRCs中向顶端横纹状体的运输。
Polarized exocytosis plays a major role in development and cell differentiation but the mechanisms that target exocytosis to specific membrane domains in animal cells are still poorly understood. We characterized Drosophila Sec6, a component of the exocyst complex that is believed to tether secretory vesicles to specific plasma membrane sites. sec6 mutations cause cell lethality and disrupt plasma membrane growth. In developing photoreceptor cells (PRCs), Sec6 but not Sec5 or Sec8 shows accumulation at adherens junctions. In late PRCs, Sec6, Sec5, and Sec8 colocalize at the rhabdomere, the light sensing subdomain of the apical membrane. PRCs with reduced Sec6 function accumulate secretory vesicles and fail to transport proteins to the rhabdomere, but show normal localization of proteins to the apical stalk membrane and the basolateral membrane. Furthermore, we show that Rab11 forms a complex with Sec5 and that Sec5 interacts with Sec6 suggesting that the exocyst is a Rab11 effector that facilitates protein transport to the apical rhabdomere in Drosophila PRCs.