Internalization of caveolae and their relationship with endosomes in cultured human and mouse endothelial cells
Internalization of caveolae and their relationship with endosomes in cultured human and mouse endothelial cells
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DOI：
10.1111/j.1447-073x.2006.00160.x
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发表时间：
2007-06-01
影响因子：
1.2
通讯作者：
Takata, Kuniaki
中科院分区：
文献类型：
--
作者：
Aoki, Takeo;Hagiwara, Haruo;Takata, Kuniaki
用过钒酸盐或钒酸盐处理细胞诱导小窝蛋白-1的磷酸化及其从细胞表面的内化，但小窝的细胞内命运尚未完全阐明。在本研究中，我们研究了人脐静脉内皮细胞和小鼠内皮细胞KOP 2.16细胞内吞小窝的命运。通过免疫荧光显微镜以及免疫沉淀和生物素化转铁蛋白的追逐，检查内化小窝的定位及其与内体的关系。在未处理的细胞中，小窝蛋白-1主要局限于细胞表面。当细胞用过钒酸盐处理30 min或钒酸盐处理3 h时，细胞内形成许多小窝蛋白-1标记的囊泡，其中一些与Rab 5或Rab 4共定位。内化的小窝蛋白-1与内吞的转铁蛋白共定位在Rab 5-，Rab 4-或早期内体抗原-1-标记的隔室中，其中小窝蛋白-1被磷酸化。然后它移动到Rab 11相关的隔间。免疫金电子显微镜显示，内化小窝蛋白-1共定位与Rab 5或Rab 4的囊泡大于小窝。这些结果表明，内化小窝与早期内体相互作用。
Treatment of cells with pervanadate or vanadate induces the phosphorylation of caveolin-1 and its internalization from the cell surface, but the intracellular fate of caveolae has not been fully elucidated. In the present study, we examined the fate of endocytosed caveolae in human umbilical vein endothelial cells and mouse endothelial KOP2.16 cells. The localization of internalized caveolae and their relationship with the endosomes were examined by immunofluorescence microscopy as well as by immunoprecipitation and chasing of biotinylated transferrin. In untreated cells, caveolin-1 was mostly confined to the cell surface. When cells were treated with either pervanadate for 30 min or vanadate for 3 h, many caveolin-1-labeled vesicles were formed inside the cells, some of which were colocalized with Rab5 or Rab4. The internalized caveolin-1 was colocalized with the endocytosed transferrin in the Rab5-, Rab4- or early endosome antigen-1-labeled compartment where caveolin-1 was phosphorylated. It then moved to the Rab11-associated compartment. Immunogold electron microscopy revealed that internalized caveolin-1 colocalized with Rab5 or Rab4 in vesicles larger than caveolae. These results suggest that the internalized caveolae interact with early endosomes.