The role of the tethering proteins p115 and GM130 in transport through the Golgi apparatus in vivo
The role of the tethering proteins p115 and GM130 in transport through the Golgi apparatus in vivo
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DOI：
10.1091/mbc.11.2.635
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发表时间：
2000-02-01
影响因子：
3.3
通讯作者：
Warren, G
中科院分区：
文献类型：
--
作者：
Seemann, J;Jokitalo, EJ;Warren, G
生化数据表明，COPI 包被的囊泡通过至少三种蛋白质的复合物束缚在高尔基体膜上：p115、giantin 和 GM130。 p115 与囊泡上的巨蛋白结合，并与膜上的 GM130 结合。我们现在检查这种束缚复合物在体内的功能。显微注射 GM130 的 N 端肽或过表达缺乏该 N 端肽的 GM130 会抑制 p115 与高尔基体膜的结合。对单个显微注射细胞的电子显微镜分析表明，高尔基体区域中 COP 大小的转运囊泡的数量大幅增加，表明转运囊泡继续出芽，但融合能力较差。定量免疫荧光分析证实了这一点，结果表明VSV-G蛋白的细胞内转运被显着抑制。总之，这些数据表明，这种束缚复合物提高了运输囊泡与其目标膜融合的效率。它们还为有丝分裂高尔基体断裂模型提供了支持，其中束缚复合物被 GM130 有丝分裂磷酸化破坏。
Biochemical data have shown that COPI-coated vesicles are tethered to Golgi membranes by a complex of at least three proteins: p115, giantin, and GM130. p115 binds to giantin on the vesicles and to GM130 on the membrane. We now examine the function of this tethering complex in vivo. Microinjection of an N-terminal peptide of GM130 or overexpression of GM130 lacking this N-terminal peptide inhibits the binding of p115 to Golgi membranes. Electron microscopic analysis of single microinjected cells shows that the number of COP-sized transport vesicles in the Golgi region increases substantially, suggesting that transport vesicles continue to bud but are less able to fuse. This was corroborated by quantitative immunofluorescence analysis, which showed that the intracellular transport of the VSV-G protein was significantly inhibited. Together, these data suggest that this tethering complex increases the efficiency with which transport vesicles fuse with their target membrane. They also provide support for a model of mitotic Golgi fragmentation in which the tethering complex is disrupted by mitotic phosphorylation of GM130.