Secretory cargo composition affects polarized secretion in MDCK epithelial cells.
Secretory cargo composition affects polarized secretion in MDCK epithelial cells.
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分泌货物成分影响 MDCK 上皮细胞的极化分泌。
DOI：
10.1007/s11010-007-9666-4
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发表时间：
2008
影响因子：
4.3
通讯作者：
Gorr,Sven-Ulrik
中科院分区：
文献类型：
--
作者：
Fasciotto,BrigitteH;Kühn,Ulrike;Cohn,DavidV;Gorr,Sven-Ulrik
极化上皮细胞在顶端或基底外侧细胞表面分泌蛋白质。许多非上皮分泌蛋白在极化上皮细胞中表达时也表现出极化分泌，但很难预测外源蛋白在上皮细胞中的分泌位置。这个问题是令人感兴趣的，因为分泌性上皮被认为是基因治疗方案的靶组织，目的是表达治疗性分泌蛋白。在甲状旁腺中，甲状旁腺激素由弗林蛋白酶处理，并与嗜铬粒蛋白A共同储存在分泌颗粒中。为了测试这些蛋白质在上皮细胞中的分泌，将它们在MDCK细胞中表达。嗜铬粒蛋白A和弗林蛋白酶的分泌形式分泌的顶部，而甲状旁腺激素分泌60%的基底外侧。然而，在嗜铬粒蛋白A的存在下，甲状旁腺激素的分泌是65%的顶端，这表明嗜铬粒蛋白可以作为甲状旁腺激素的“排序护送”（排序伴侣）。相反，顶部分泌弗林蛋白酶不影响甲状旁腺激素的排序。嗜铬粒蛋白A的顶端分泌依赖于胆固醇，这表明这种蛋白质使用一个既定的细胞分选机制顶端分泌。然而，这种分选不涉及嗜铬粒蛋白A的N-末端膜结合结构域。这些结果表明，外源分泌蛋白可以被用作“分选护送”，以指导分泌蛋白的顶端分泌途径，而不改变分泌蛋白的一级结构。这种系统可用于从上皮细胞靶向表达分泌蛋白。
Polarized epithelial cells secrete proteins at either the apical or basolateral cell surface. A number of non-epithelial secretory proteins also exhibit polarized secretion when they are expressed in polarized epithelial cells but it is difficult to predict where foreign proteins will be secreted in epithelial cells. The question is of interest since secretory epithelia are considered as target tissues for gene therapy protocols that aim to express therapeutic secretory proteins. In the parathyroid gland, parathyroid hormone is processed by furin and co-stored with chromogranin A in secretory granules. To test the secretion of these proteins in epithelial cells, they were expressed in MDCK cells. Chromogranin A and a secreted form of furin were secreted apically while parathyroid hormone was secreted 60% basolaterally. However, in the presence of chromogranin A, the secretion of parathyroid hormone was 65% apical, suggesting that chromogranin can act as a “sorting escort” (sorting chaperone) for parathyroid hormone. Conversely, apically secreted furin did not affect the sorting of parathyroid hormone. The apical secretion of chromogranin A was dependent on cholesterol, suggesting that this protein uses an established cellular sorting mechanism for apical secretion. However, this sorting does not involve the N-terminal membrane-binding domain of chromogranin A. These results suggest that foreign secretory proteins can be used as “sorting escorts” to direct secretory proteins to the apical secretory pathway without altering the primary structure of the secreted protein. Such a system may be of use in the targeted expression of secretory proteins from epithelial cells.