van Meer G, Simons K
European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany.
J Cell Biochem. 1988 Jan;36(1):51-8. doi: 10.1002/jcb.240360106.
Apical and basolateral membrane domains of epithelial cell plasma membranes possess unique lipid compositions. The tight junction, the structure separating the two domains, forms a diffusion barrier for membrane components and thereby prevents intermixing of the two sets of lipids. The barrier apparently resides in the outer, exoplasmic leaflet of the plasma membrane bilayer. First data are now available on the generation of these differences in Madin-Darby canine kidney (MDCK) cells, grown on filter supports. Experiments in which fluorescent precursors of apical lipids were introduced into the cell have demonstrated that upon biosynthesis apical lipids are sorted from basolateral lipids in an intracellular compartment. In this paper we present a model for the sorting process, the central point of which is that the two sets of lipids laterally segregate into microdomains that bud to form vesicles delivering the lipids to the apical and the basolateral plasma membrane domains, respectively.
上皮细胞质膜的顶端和基底外侧膜结构域具有独特的脂质组成。紧密连接是分隔这两个结构域的结构，它形成了膜成分的扩散屏障，从而防止两组脂质混合。该屏障显然存在于质膜双层的外侧、外质小叶中。现在有关于在滤膜支持物上生长的Madin-Darby犬肾（MDCK）细胞中这些差异产生的首批数据。将顶端脂质的荧光前体引入细胞的实验表明，在生物合成过程中，顶端脂质在细胞内区室中与基底外侧脂质分选。在本文中，我们提出了一个分选过程的模型，其核心要点是两组脂质横向分离成微结构域，这些微结构域出芽形成囊泡，分别将脂质递送至顶端和基底外侧质膜结构域。
