A di-acidic (DXE) code directs concentration of cargo during export from the endoplasmic reticulum
A di-acidic (DXE) code directs concentration of cargo during export from the endoplasmic reticulum
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DOI：
10.1074/jbc.274.22.15937
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发表时间：
1999-05-28
影响因子：
4.8
通讯作者：
Balch, WE
中科院分区：
文献类型：
--
作者：
Nishimura, N;Bannykh, S;Balch, WE
水疱性口炎病毒糖蛋白（Vm-G）（一种 I 型跨膜蛋白）从内质网的有效输出需要位于胞质羧基末端尾部的二酸代码（DXE）（Nishimura, N, 和 Balch, W, E, (1997) Science 277, 558-558），通过突变来突变 DXE 代码AXA 不会阻止 VSV-G 招募到在 Sari 和 Sec23/24 复合体（COPII 出芽机制的组成部分）的激活形式存在下形成的出芽前复合体。然而，在囊泡分裂之前的后续浓缩步骤中需要信号。通过使用绿色荧光蛋白标记的 VSV-G 对单个细胞中的运动进行成像，我们发现缺乏 DXE 代码的 VSV-G 无法浓缩到 COPII 囊泡中。结果，下游前高尔基体中间体和高尔基体区室中 VSV-G 稳态浓度正常增加 5-10 倍的情况消失了。这些结果首次证明 DXE 信号失活使早期货物选择步骤从浓缩到 COPII 解耦。囊泡。我们建议从内质网有效输出需要两个连续的步骤。
Efficient export of vesicular stomatitis virus glycoprotein (Vm-G), a type I transmembrane protein, from the endoplasmic reticulum requires a di-acidic code (DXE) located in the cytosolic carboxyl-terminal tail (Nishimura, N,, and Balch, W, E, (1997) Science 277, 558-558), Mutation of the DXE code by mutation to AXA did not prevent VSV-G recruitment to pre-budding complexes formed in the presence of the activated form of the Sari and the Sec23/24 complex, components of the COPII budding machinery. However, the signal was required at a subsequent concentration step preceding vesicle fission. By using green fluorescence protein-tagged VSV-G to image movement in a single cell, we found that VSV-G lacking the DXE code fails to be concentrated into COPII vesicles. As a result, the normal 5-10-fold increase in the steady-state concentration of VSV-G in downstream pre-Golgi intermediates and Golgi compartments was lost. These results demonstrate for the first time that inactivation of the DXE signal uncouples early cargo selection steps from concentration into COPII. vesicles. We propose that two sequential steps are required for efficient export from the endoplasmic reticulum.