Imaging of procollagen transport reveals COPI-dependent cargo sorting during ER-to-Golgi transport in mammalian cells.
Imaging of procollagen transport reveals COPI-dependent cargo sorting during ER-to-Golgi transport in mammalian cells.
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发表时间：
2002-03
影响因子：
4
通讯作者：
D. Stephens;R. Pepperkok
中科院分区：
文献类型：
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作者：
D. Stephens;R. Pepperkok
我们已经研究了前胶原的ER到高尔基体的转运，当在ER的内腔中组装时，前胶原被认为是物理上太大而不能适合经典描述的60-80 nm COPI和COPII包被的转运囊泡。我们发现，前胶原通过COPII包被的ER出口位点离开ER，并在确定的转运复合物中沿沿着微管转运到高尔基体。然而，这些含有前胶原的转运复合物与含有其他货物蛋白如ERGIC-53和ts-045-G的转运复合物不同。此外，与含有ts-045-G的那些相比，它们不标记COPI包衣复合物。在加入前胶原折叠所需的抗坏血酸盐之前抑制COPII或COPI功能可抑制前胶原从ER的输出。加入抗坏血酸后，COPI外壳功能失活导致前胶原定位于转运复合物，该复合物现在也含有ERGIC-53，并在其转运至高尔基复合物时受到抑制。这些数据揭示了哺乳动物细胞中存在早期COPI依赖性的前高尔基体货物分选步骤。
We have examined the ER-to-Golgi transport of procollagen, which, when assembled in the lumen of the ER, is thought to be physically too large to fit in classically described 60-80 nm COPI- and COPII-coated transport vesicles. We found that procollagen exits the ER via COPII- coated ER exit sites and is transported to the Golgi along microtubules in defined transport complexes. These procollagen-containing transport complexes are, however, distinct from those containing other cargo proteins like ERGIC-53 and ts-045-G. Furthermore, they do not label for the COPI coat complex in contrast to those containing ts-045-G. Inhibition of COPII or COPI function before addition of ascorbate, which is required for the folding of procollagen, inhibits export of procollagen from the ER. Inactivation of COPI coat function after addition of ascorbate results in the localisation of procollagen to transport complexes that now also contain ERGIC-53 and are inhibited in their transport to the Golgi complex. These data reveal the existence of an early COPI-dependent, pre-Golgi cargo sorting step in mammalian cells.