Sorting of membrane and fluid at the apical pole of polarized Madin-Darby canine kidney cells
Sorting of membrane and fluid at the apical pole of polarized Madin-Darby canine kidney cells
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DOI：
10.1091/mbc.11.6.2131
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发表时间：
2000-06-01
影响因子：
3.3
通讯作者：
Apodaca, G
中科院分区：
文献类型：
--
作者：
Leung, SM;Ruiz, WG;Apodaca, G
当流体相标记物从极化的Madin-Darby犬肾细胞的相反两极内化时，它们在晚期内体中相遇之前在不同的顶端和基底外侧早期内体中积累。最近的证据表明，显着的混合顶部和基底外侧内化。膜蛋白存在于专门的顶端内体区室中，包括共同再循环内体和顶端再循环内体（ARE）。这些后者的车厢和液体标记的顶端早期内涵体之间的关系是未知的，目前。我们报告说，当顶端回收，标记，膜结合免疫球蛋白A（多聚免疫球蛋白受体的配体），和液相葡聚糖共同内化从Madin-Darby犬肾细胞的顶端极点，他们进入一个共享的顶端早期内涵体（小于或等于2.5分钟，在37摄氏度），然后迅速分离。葡聚糖保留在大的核上EEA 1阳性早期内体中，而再循环聚合免疫球蛋白受体结合的免疫球蛋白A被递送到Rab 11阳性的亚顶端再循环区室。后一步需要完整的微管细胞骨架。受体结合的转铁蛋白，基底外侧循环途径的标志物，具有有限的访问的流体丰富的顶端早期内体，但被排除在外的Rab 11阳性循环室的亚顶端元素。我们建议使用术语ARE来描述顶端下Rab 11阳性隔室，并且ARE与富含转铁蛋白的共同再循环内体和富含液体的顶端早期内体不同。
When fluid-phase markers are internalized from opposite poles of polarized Madin-Darby canine kidney cells, they accumulate in distinct apical and basolateral early endosomes before meeting in late endosomes. Recent evidence suggests that significant mixing of apically and basolaterally internalized. membrane proteins occurs in specialized apical endosomal compartments, including the common recycling endosome and the apical recycling endosome (ARE). The relationship between these latter compartments and the fluid-labeled apical early endosome is unknown at present. We report that when the apical recycling, marker, membrane-bound immunoglobulin A (a ligand for the polymeric immunoglobulin receptor), and fluid-phase dextran are cointernalized from the apical poles of Madin-Darby canine kidney cells, they enter a shared apical early endosome (less than or equal to 2.5 min at 37 degrees C) and are then rapidly segregated from one another. The dextran remains in the large supranuclear EEA1-positive early endosomes while recycling polymeric immunoglobulin receptor-bound immunoglobulin A is delivered to a Rab11-positive subapical recycling compartment. This latter step requires an intact microtubule cytoskeleton. Receptor-bound transferrin, a marker of the basolateral recycling pathway, has limited access to the fluid-rich apical early endosome but is excluded from the subapical elements of the Rab11-positive recycling compartment. We propose that the term ARE be used to describe the subapical Rab11-positive compartment and that the ARE is distinct from both the transferrin-rich common recycling endosome and the fluid-rich apical early endosome.