Department of Cell Biology, University of Seville, 41012 Seville, Spain.
Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain.
Int J Mol Sci. 2019 Jul 17;20(14):3506. doi: 10.3390/ijms20143506.
Protein export from the endoplasmic reticulum (ER) is an essential process in all eukaryotes driven by the cytosolic coat complex COPII, which forms vesicles at ER exit sites for transport of correctly assembled secretory cargo to the Golgi apparatus. The COPII machinery must adapt to the existing wide variety of different types of cargo proteins and to different cellular needs for cargo secretion. The study of the ER export of glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs), a special glycolipid-linked class of cell surface proteins, is contributing to address these key issues. Due to their special biophysical properties, GPI-APs use a specialized COPII machinery to be exported from the ER and their processing and maturation has been recently shown to actively regulate COPII function. In this review, we discuss the regulatory mechanisms by which GPI-APs are assembled and selectively exported from the ER.
内质网（ER）中的蛋白质输出是所有真核生物的基本过程，由胞质外套复合 COPII 驱动，该复合物在 ER 出口部位形成囊泡，以将正确组装的分泌货物运输到高尔基体。COPII 机制必须适应现有的各种不同类型的货物蛋白和不同的货物分泌细胞需求。对糖基磷脂酰肌醇（GPI）锚定蛋白（GPI-AP）的 ER 输出的研究有助于解决这些关键问题，GPI-AP 是一类特殊的糖脂连接的细胞表面蛋白。由于其特殊的物理化学性质，GPI-AP 利用专门的 COPII 机制从 ER 中输出，最近的研究表明，它们的加工和成熟可以主动调节 COPII 的功能。在这篇综述中，我们讨论了 GPI-AP 组装和从 ER 中选择性输出的调节机制。
