The cytoskeletal motor proteins Dynein and MyoV direct apical transport of Crumbs
The cytoskeletal motor proteins Dynein and MyoV direct apical transport of Crumbs
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DOI：
10.1016/j.ydbio.2019.12.009
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发表时间：
2020-03-15
影响因子：
2.7
通讯作者：
Thompson, B. J.
中科院分区：
文献类型：
--
作者：
Aguilar-Aragon, M.;Fletcher, G.;Thompson, B. J.
Crumbs(果蝇中的CRB；哺乳动物中的CRB1-3)是上皮细胞极性的跨膜决定因素，也是河马信号的调节因子。CRB通常定位于顶端细胞-细胞接触，就在粘连连接的上方，但CRB在上皮细胞中的顶端转运如何调节仍不清楚。我们使用果蝇卵泡上皮来证明CRB的极化运输是由运动蛋白Dynein沿着微管和由运动蛋白MyoV(MyoV)沿着肌动蛋白细丝介导的。用Dynein或MyoV阻断含有CRB的囊泡的运输会导致CRB在Rab11内体内积聚，而不是顶端递送。CRB在质膜上传递和稳定的最后步骤需要胞外复合体和三个顶端FERM结构域蛋白-Merlin、Moesin和Expanded-它们的同时丢失扰乱了CRB的顶端定位。因此，CRB FERM结合基序(FBM)的敲入缺失也会损害顶端定位。最后，CRB的过度表达挑战了这一系统，创造了一个敏化的背景，以确定参与细胞骨架极化、顶膜运输和顶端区域CRB稳定的成分。
Crumbs (Crb in Drosophila; CRB1-3 in mammals) is a transmembrane determinant of epithelial cell polarity and a regulator of Hippo signalling. Crb is normally localized to apical cell-cell contacts, just above adherens junctions, but how apical trafficking of Crb is regulated in epithelial cells remains unclear. We use the Drosophila follicular epithelium to demonstrate that polarized trafficking of Crb is mediated by transport along microtubules by the motor protein Dynein and along actin filaments by the motor protein Myosin-V (MyoV). Blocking transport of Crb-containing vesicles by Dynein or MyoV leads to accumulation of Crb within Rab11 endosomes, rather than apical delivery. The final steps of Crb delivery and stabilisation at the plasma membrane requires the exocyst complex and three apical FERM domain proteins - Merlin, Moesin and Expanded - whose simultaneous loss disrupts apical localization of Crb. Accordingly, a knock-in deletion of the Crb FERM-binding motif (FBM) also impairs apical localization. Finally, overexpression of Crb challenges this system, creating a sensitized background to identify components involved in cytoskeletal polarization, apical membrane trafficking and stabilisation of Crb at the apical domain.