Grindstaff K K, Yeaman C, Anandasabapathy N, Hsu S C, Rodriguez-Boulan E, Scheller R H, Nelson W J
Department of Molecular and Cellular Physiology, Stanford University School of Medicine, California 94305-5345, USA.
Cell. 1998 May 29;93(5):731-40. doi: 10.1016/s0092-8674(00)81435-x.
In budding yeast, the Sec6/8p complex is essential for generating cell polarity by specifying vesicle delivery to the bud tip. We show that Sec6/8 homologs are components of a cytosolic, approximately 17S complex in nonpolarized MDCK epithelial cells. Upon initiation of calcium-dependent cell-cell adhesion, approximately 70% of Sec6/8 is rapidly (t(1/2) approximately 3-6 hr) recruited to sites of cell-cell contact. In streptolysin-O-permeabilized MDCK cells, Sec8 antibodies inhibit delivery of LDL receptor to the basal-lateral membrane, but not p75NTR to the apical membrane. These results indicate that lateral membrane recruitment of the Sec6/8 complex is a consequence of cell-cell adhesion and is essential for the biogenesis of epithelial cell surface polarity.
在出芽酵母中，Sec6/8p复合物通过指定囊泡向芽尖的运输对于产生细胞极性至关重要。我们发现，Sec6/8同源物是非极化的MDCK上皮细胞中一种约17S胞质复合物的组成成分。在钙依赖性细胞间黏附开始时，约70%的Sec6/8迅速（半衰期约3 - 6小时）被募集到细胞间接触位点。在经链球菌溶血素O通透处理的MDCK细胞中，Sec8抗体抑制低密度脂蛋白受体向基底外侧膜的运输，但不抑制p75NTR向顶膜的运输。这些结果表明，Sec6/8复合物向侧面膜的募集是细胞间黏附的结果，并且对于上皮细胞表面极性的生物发生至关重要。
