A comparison of caveolae and caveolin-1 to folate receptor α in retina and retinal pigment epithelium
A comparison of caveolae and caveolin-1 to folate receptor α in retina and retinal pigment epithelium
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DOI：
10.1023/a:1017991925821
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发表时间：
2001-01-01
期刊：
影响因子：
--
通讯作者：
Smith, SB
中科院分区：
文献类型：
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作者：
Bridges, CC;El-Sherbeny, A;Smith, SB
凹陷是存在于大多数哺乳动物细胞中的烧瓶状膜凹陷。它们的区别在于存在由蛋白质小窝蛋白组成的条纹皮毛。小窝参与了许多细胞过程，包括细胞增多症，小窝被认为与叶酸受体α共定位，并参与叶酸摄取。我们实验室最近将叶酸受体α定位于视网膜色素上皮(RPE)的基底外侧表面。它也存在于视网膜的许多其他细胞中。在目前的研究中，我们询问RPE中是否存在小凹，如果是，它们的分布模式是否类似于叶酸受体α。我们还检测了小窝蛋白-1的分布模式，它可以作为小窝的一个标志。广泛的电子显微镜分析显示与内皮细胞相关的小凹。然而，在完整或培养的RPE中均未检测到。激光扫描共聚焦显微镜分析完整的RPE，将小窝蛋白-1定位于根尖和基底面，这与叶酸受体α的分布不同。Western分析证实培养的RPE细胞中存在小窝蛋白-1，激光扫描共聚焦显微镜将该蛋白定位于RPE的基底膜，类似于叶酸受体α的分布。这一分布通过电子显微镜免疫定位得到证实。RPE中缺乏小凹表明，这些结构可能不是RPE中叶酸内化所必需的。
Caveolae are flask-shaped membrane invaginations present in most mammalian cells. They are distinguished by the presence of a striated coat composed of the protein, caveolin. Caveolae have been implicated in numerous cellular processes, including potocytosis in which caveolae are hypothesized to co-localize with folate receptor alpha and participate in folate uptake. Our laboratory has recently localized folate receptor alpha to the basolateral surface of the retinal pigment epithelium (RPE). It is present also in many other cells of the retina. In the present study, we asked whether caveolae were present in the RPE, and if so, whether their pattern of distribution was similar to folate receptor alpha. We also examined the distribution pattern of caveolin-1, which can be a marker of caveolae. Extensive electron microscopical analysis revealed caveolae associated with endothelial cells. However, none were detected in intact or cultured RPE. Laser scanning confocal microscopical analysis of intact RPE localized caveolin-1 to the apical and basal surfaces, a distribution unlike folate receptor alpha. Western analysis confirmed the presence of caveolin-1 in cultured RPE cells and laser scanning confocal microscopy localized the protein to the basal plasma membrane of the RPE, a distribution like that of folate receptor alpha. This distribution was confirmed by electron microscopic immunolocalization. The lack of caveolae in the RPE suggests that these structures may not be essential for folate internalization in the RPE.