A novel clathrin adaptor complex mediates basolateral targeting in polarized epithelial cells
A novel clathrin adaptor complex mediates basolateral targeting in polarized epithelial cells
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DOI：
10.1016/s0092-8674(00)81650-5
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发表时间：
1999-10-15
期刊：
影响因子：
64.5
通讯作者：
Mellman, I
中科院分区：
文献类型：
--
作者：
Fölsch, H;Ohno, H;Mellman, I
尽管极化的上皮细胞因能维持明显不同的顶膜和基底外侧质膜区域而广为人知，但负责将膜蛋白靶向运输到顶膜或基底外侧表面的机制一直难以捉摸。我们已经鉴定出一种新型的AP - 1网格蛋白衔接蛋白复合物，它包含μ1B作为其亚基之一，μ1B是普遍表达的μ1A的一种上皮细胞特异性同源物。LLC - PK1肾上皮细胞不表达μ1B，并将许多基底外侧蛋白错误分选到顶膜表面。μ1B的稳定表达选择性地恢复了基底外侧靶向运输，改善了LLC - PK1单层细胞的整体组织结构，且对顶膜靶向运输没有影响。我们得出结论，基底外侧分选是由包含μ1B的上皮细胞特异性AP - 1复合物介导的。
Although polarized epithelial cells are well known to maintain distinct apical and basolateral plasma membrane domains, the mechanisms responsible for targeting membrane proteins to the apical or basolateral surfaces have remained elusive. We have identified a novel form of the AP-1 clathrin adaptor complex that contains as one of its subunits mu 1B, an epithelial cell-specific homolog of the ubiquitously expressed mu 1A. LLC-PK1 kidney epithelial cells do not express mu 1B and missort many basolateral proteins to the apical surface. Stable expression of mu 1B selectively restored basolateral targeting, improved the overall organization of LLC-PK1 monolayers, and had no effect on apical targeting. We conclude that basolateral sorting is mediated by an epithelial cell-specific version of the AP-1 complex containing mu 1B.