The recycling pathway of protein ERGIC-53 and dynamics of the ER-Golgi intermediate compartment.
The recycling pathway of protein ERGIC-53 and dynamics of the ER-Golgi intermediate compartment.
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发表时间：
1998-11
影响因子：
4
通讯作者：
Judith Klumperman;A. Schweizer;Henrik Clausen;Bor Luen Tang;Wanjin Hong;V. Oorschot;Hans-Peter Hauri
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文献类型：
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作者：
Judith Klumperman;A. Schweizer;Henrik Clausen;Bor Luen Tang;Wanjin Hong;V. Oorschot;Hans-Peter Hauri
为了建立早期分泌途径中的回收途径，我们研究了 HepG2 细胞中 ER-高尔基中间室 (ERGIC) 标记物 ERGIC-53 的回收。免疫荧光显微镜显示 15°C 时 ERGIC-53 在高尔基体区域逐渐浓度。复温至 37°C 后，ERGIC-53 通常通过管状突起重新分布到细胞外周，该管状突起很大程度上排除了顺行转运的白蛋白。对 37°C 培养的细胞进行免疫金标记显示，ERGIC-53 主要存在于高尔基体附近和细胞外周的特征性 β-COP 阳性管泡簇中。 15℃时ERGIC-53的浓度是由ERGIC-53在ERGIC中的积累以及ERGIC膜靠近高尔基体的移动造成的。回温至 37°C 后，ERGIC 中的 ERGIC-53 标记迅速恢复到正常水平，而顺式高尔基体中的 ERGIC-53 标记没有变化。温度控制对 ERGIC-53 簇的平均数量没有影响。密度梯度离心表明，15℃下ERGIC中积累的多余ERGIC-53在复温后迅速转运至ER。这些结果表明 ERGIC 是由恒定平均数量的簇组成的动态膜系统，并且 ERGIC-53 的主要回收途径绕过高尔基体。
To establish recycling routes in the early secretory pathway we have studied the recycling of the ER-Golgi intermediate compartment (ERGIC) marker ERGIC-53 in HepG2 cells. Immunofluorescence microscopy showed progressive concentration of ERGIC-53 in the Golgi area at 15 degreesC. Upon rewarming to 37 degreesC ERGIC-53 redistributed into the cell periphery often via tubular processes that largely excluded anterograde transported albumin. Immunogold labeling of cells cultured at 37 degreesC revealed ERGIC-53 predominantly in characteristic beta-COP-positive tubulo-vesicular clusters both near the Golgi apparatus and in the cell periphery. Concentration of ERGIC-53 at 15 degreesC resulted from both accumulation of ERGIC-53 in the ERGIC and movement of ERGIC membranes closer to the Golgi apparatus. Upon rewarming to 37 degreesC the labeling of ERGIC-53 in the ERGIC rapidly returned to normal levels whereas ERGIC-53's labeling in the cis-Golgi was unchanged. Temperature manipulations had no effect on the average number of ERGIC-53 clusters. Density gradient centrifugation indicated that the surplus ERGIC-53 accumulating in the ERGIC at 15 degreesC was rapidly transported to the ER upon rewarming. These results suggest that the ERGIC is a dynamic membrane system composed of a constant average number of clusters and that the major recycling pathway of ERGIC-53 bypasses the Golgi apparatus.