Association of Rab25 and Rab11a with the apical recycling system of polarized Madin-Darby canine kidney cells
Association of Rab25 and Rab11a with the apical recycling system of polarized Madin-Darby canine kidney cells
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DOI：
10.1091/mbc.10.1.47
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发表时间：
1999-01-01
影响因子：
3.3
通讯作者：
Goldenring, JR
中科院分区：
文献类型：
--
作者：
Casanova, JE;Wang, XY;Goldenring, JR
最近的证据表明，顶端和基底外侧的内吞途径在上皮细胞会聚在一个位于顶端的，被称为顶端再循环内体的内体室的中心周围。在该隔室中，顶部和基底外侧内化的膜成分被认为被分选用于再循环回到它们的起源位点或用于转胞吞到相对的质膜结构域。我们在这里报告，在上皮细胞系Madin-Darby犬肾（MDCK），Rab 11 a的抗体标记的顶端pericentriolar内体室，是依赖于完整的微管的完整性。此外，该隔室可接近从顶端或基底外侧极内化的膜结合标记物（二聚免疫球蛋白A [伊加]），功能上将其定义为顶端再循环内体。我们还研究了密切相关的上皮特异性Rab，Rab 25，在MDCK细胞膜回收和胞吞转运的调节中的作用。将Rab 25基因转染MDCK细胞后，发现Rab 11 a与Rab 25共定位于细胞亚顶端囊泡中。Rab 25转染也改变了Rab 11 a的分布，导致免疫反应性聚结成多个与中心体无关的致密囊泡结构。然而，诺考达唑仍然分散这些囊泡，和二聚体伊加内化从顶或基底侧膜中检测到标记的内体与Rab 11 a和Rab 25的抗体。Rab 25的过表达降低了伊加转胞吞率和顶端，但不是基底侧，再循环的内在配体。相反，显性阴性Rab 25 T26 N的表达并没有改变顶端回收或胞吞转运。这些结果表明Rab 11 a和Rab 25都与上皮细胞的顶端再循环系统相关，并表明Rab 25可能选择性地调节顶端再循环和/或胞吞途径。
Recent evidence suggests that apical and basolateral endocytic pathways in epithelia converge in an apically located, pericentriolar endosomal compartment termed the apical recycling endosome. In this compartment, apically and basolaterally internalized membrane constituents are thought to be sorted for recycling back to their site of origin or for transcytosis to the opposite plasma membrane domain. We report here that in the epithelial cell line Madin-Darby Canine Kidney (MDCK), antibodies to Rab11a label an apical pericentriolar endosomal compartment that is dependent on intact microtubules for its integrity. Furthermore, this compartment is accessible to a membrane-bound marker (dimeric immunoglobulin A [IgA]) internalized from either the apical or basolateral pole, functionally defining it as the apical recycling endosome. We have also examined the role of a closely related epithelial-specific Rab, Rab25, in the regulation of membrane recycling and transcytosis in MDCK cells. When cDNA encoding Rab25 was transfected into MDCK cells, the protein colocalized with Rab11a in subapical vesicles. Rab25 transfection also altered the distribution of Rab11a, causing the coalescence of immunoreactivity into multiple denser vesicular structures not associated with the centrosome. Nevertheless, nocodazole still dispersed these vesicles, and dimeric IgA internalized from either the apical or basolateral membrane was detected in endosomes labeled with antibodies to both Rab11a and Rab25. Overexpression of Rab25 decreased the rate of IgA transcytosis and of apical, but not basolateral, recycling of internalized ligand. Conversely, expression of the dominant-negative Rab25T26N did not alter either apical recycling or transcytosis. These results indicate that both Rab11a and Rab25 associate with the apical recycling system of epithelial cells and suggest that Rab25 may selectively regulate the apical recycling and/or transcytotic pathways.