Sequential coupling between COPII and COPI vesicle coats in endoplasmic reticulum to Golgi transport.
Sequential coupling between COPII and COPI vesicle coats in endoplasmic reticulum to Golgi transport.
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DOI：
10.1083/jcb.131.4.875
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发表时间：
1995-11
期刊：
影响因子：
--
通讯作者：
Balch WE
中科院分区：
文献类型：
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作者：
Aridor M;Bannykh SI;Rowe T;Balch WE
COPI和COPII是囊泡外壳复合物，其组装分别受ARF1和Sar1 gtpase调控。我们发现，COPI和COPII外壳复合物分别独立地募集到哺乳动物细胞的ER （COPII）、前高尔基体（COPI、COPII）和高尔基体（COPI）膜上。为了确定它们在内质网到高尔基体运输中的作用，我们使用了阶段特异性的体外运输试验来同步货物在高尔基体前中间体之间的运动，以及GDP和gtp限制形式的Sar1和ARF1蛋白来控制外壳招募。我们发现COPII仅负责内质网的输出，在囊泡出芽后迅速丢失，并介导由囊泡簇和小管元件组成的前高尔基中间体的建立所需的囊泡步骤。COPI被招募到前高尔基体上，在那里它启动顺行转运蛋白水泡性口炎病毒糖蛋白（VSV-G）与逆行转运蛋白p58的分离，p58是一种在内质网和前高尔基体之间积极循环的蛋白质。我们提出COPII和COPI外壳之间的顺序偶联对于协调和指导内质网和参与蛋白质向高尔基复合物运输的前高尔基中间体之间的双向囊泡运输至关重要。
COPI and COPII are vesicle coat complexes whose assembly is regulated by the ARF1 and Sar1 GTPases, respectively. We show that COPI and COPII coat complexes are recruited separately and independently to ER (COPII), pre-Golgi (COPI, COPII), and Golgi (COPI) membranes of mammalian cells. To address their individual roles in ER to Golgi transport, we used stage specific in vitro transport assays to synchronize movement of cargo to and from pre-Golgi intermediates, and GDP- and GTP-restricted forms of Sar1 and ARF1 proteins to control coat recruitment. We find that COPII is solely responsible for export from the ER, is lost rapidly following vesicle budding and mediates a vesicular step required for the build-up of pre-Golgi intermediates composed of clusters of vesicles and small tubular elements. COPI is recruited onto pre-Golgi intermediates where it initiates segregation of the anterograde transported protein vesicular stomatitis virus glycoprotein (VSV-G) from the retrograde transported protein p58, a protein which actively recycles between the ER and pre-Golgi intermediates. We propose that sequential coupling between COPII and COPI coats is essential to coordinate and direct bi-directional vesicular traffic between the ER and pre-Golgi intermediates involved in transport of protein to the Golgi complex.