An apical-type trafficking pathway is present in cultured oligodendrocytes but the sphingolipid-enriched myelin membrane is the target of a basolateral-type pathway
An apical-type trafficking pathway is present in cultured oligodendrocytes but the sphingolipid-enriched myelin membrane is the target of a basolateral-type pathway
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DOI：
10.1091/mbc.9.3.599
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发表时间：
1998-03-01
影响因子：
3.3
通讯作者：
Hoekstra, D
中科院分区：
文献类型：
--
作者：
de Vries, H;Schrage, C;Hoekstra, D
髓鞘片层起源于少突胶质细胞（OLG）质膜上的不同区域，与后者相反，髓鞘膜相对富含鞘糖脂和胆固醇。因此，OLG质膜可以被认为是由不同的膜结构域组成，如在极化细胞中;髓磷脂片让人想起顶端膜结构域，OLG质膜类似于基底外侧膜。为了揭示OLG的潜在极化膜性质，分别检查了顶侧和基底侧膜的两种典型标记物，病毒蛋白流感病毒-血凝素（HA）和水疱性口炎病毒-G蛋白（VSVG）的运输和分选。我们表明，在OLG，HA和VSVG是不同的排序，这大概发生在他们的贩运通过高尔基体。HA可以在Triton X-100不溶性部分中回收，表明顶筏型运输，而VSVG仅存在于Triton X-100可溶性部分中，与其基底外侧分选一致。因此，顶端和基底外侧分选机制似乎在OLG中起作用。然而，令人惊讶的是，VSVG被发现在细胞周围的髓磷脂片内，而HA被排除在该结构域之外。因此，尽管其筏状运输，HA不会到达显示典型的顶端膜的特征的膜。T1-Lis发现表明髓磷脂膜的独特性或需要额外的调节因子（在OLG中不存在）用于顶端递送。这些显着的结果强调了培养的OLG中膜转运的极性和调节显示出与极化细胞中的特征截然不同的特征。
Myelin sheets originate from distinct areas at the oligodendrocyte (OLG) plasma membrane and, as opposed to the latter, myelin membranes are relatively enriched in glycosphingolipids and cholesterol. The OLG plasma membrane can therefore be considered to consist of different membrane domains, as in polarized cells; the myelin sheet is reminiscent of an apical membrane domain and the OLG plasma membrane resembles the basolateral membrane. To reveal the potentially polarized membrane nature of OLG, the trafficking and sorting of two typical markers for apical and basolateral membranes, the viral proteins influenza virus-hemagglutinin (HA) and vesicular stomatitis virus-G protein (VSVG), respectively, were examined. We demonstrate that in OLG, HA and VSVG are differently sorted, which presumably occurs upon their trafficking through the Golgi. HA can be recovered in a Triton X-100-insoluble fraction, indicating an apical raft type of trafficking, whereas VSVG was only present in a Triton X-100-soluble fraction, consistent with its basolateral sorting. Hence, both an apical and a basolateral sorting mechanism appear to operate in OLG. Surprisingly, however, VSVG was found within the myelin sheets surrounding the cells, whereas HA was excluded from this domain. Therefore, despite its raft-like transport, HA does not reach a membrane that shows features typical of an apical membrane. Tl-Lis finding indicates either the uniqueness of the myelin membrane or the requirement of additional regulatory factors, absent in OLG, for apical delivery. These remarkable results emphasize that polarity and regulation of membrane transport in cultured OLG display features that are quite different from those in polarized cells.