Muñiz M, Morsomme P, Riezman H
Biozentrum of the University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland.
Cell. 2001 Jan 26;104(2):313-20. doi: 10.1016/s0092-8674(01)00215-x.
It is currently thought that all secretory proteins travel together to the Golgi apparatus where they are sorted to different destinations. However, the specific requirements for transport of GPI-anchored proteins from the endoplasmic reticulum to the Golgi apparatus in yeast could be explained if protein sorting occurs earlier in the pathway. Using an in vitro assay that reconstitutes a single round of budding from the endoplasmic reticulum, we found that GPI-anchored proteins and other secretory proteins exit the endoplasmic reticulum in distinct vesicles. Therefore, GPI-anchored proteins are sorted from other proteins, in particular other plasma membrane proteins, at an early stage of the secretory pathway. These results have wide implications for the mechanism of protein exit from the endoplasmic reticulum.
目前认为，所有分泌蛋白都会一起运输到高尔基体，在那里它们会被分拣到不同的目的地。然而，如果蛋白质分拣在该途径中更早发生，那么酵母中糖基磷脂酰肌醇（GPI）锚定蛋白从内质网运输到高尔基体的具体要求就可以得到解释。通过一种体外测定法，该方法可重建一轮从内质网出芽的过程，我们发现GPI锚定蛋白和其他分泌蛋白通过不同的囊泡离开内质网。因此，GPI锚定蛋白在分泌途径的早期就与其他蛋白质，特别是其他质膜蛋白进行了分拣。这些结果对蛋白质从内质网输出的机制具有广泛的影响。
