The yeast p24 complex regulates GPI-anchored protein transport and quality control by monitoring anchor remodeling.
The yeast p24 complex regulates GPI-anchored protein transport and quality control by monitoring anchor remodeling.
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DOI：
10.1091/mbc.e11-04-0294
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发表时间：
2011-08-15
影响因子：
3.3
通讯作者：
Muñiz M
中科院分区：
文献类型：
--
作者：
Castillon GA;Aguilera-Romero A;Manzano-Lopez J;Epstein S;Kajiwara K;Funato K;Watanabe R;Riezman H;Muñiz M
P24复合体的两个功能被描述：一是在内质网出口位点将GPI锚定蛋白与COPII蛋白连接起来，以促进它们进入内质网衍生的小泡；另一功能是用于GPI锚定蛋白的质量控制，以将未改造的GPI锚定蛋白从高尔基体取回内质网。糖基磷脂酰肌醇(GPI)锚定蛋白是一种以糖脂形式连接到真核细胞表面的分泌型蛋白。一旦GPI锚定发生在内质网(ER)的管腔中，GPI锚定上的脂类部分的结构在内质网退出之前经历了一个重塑过程。在这项研究中，我们提供的证据表明，酵母p24复合体通过与GPI锚定蛋白以锚定依赖的方式特异性结合，在它们的选择性运输中发挥双重作用。首先，p24复合体通过将重塑的GPI锚定蛋白与COPII外壳连接起来，促进重塑的GPI锚定蛋白在浓缩后有效地退出内质网，从而促进它们并入囊泡。其次，它将逃逸的、未改造的GPI锚定蛋白从高尔基体回收到COPI囊泡中的内质网。因此，p24复合体通过感知GPI锚定的状态，调节GPI锚定的蛋白在细胞内的运输，并与正确的锚定重塑相协调。
Two functions of the p24 complex are described: one connects GPI-anchored proteins to COPII proteins at ER exit sites to facilitate their incorporation into ER-derived vesicles, and the other serves in quality control of GPI-anchored proteins to retrieve unremodeled GPI-anchored proteins from the Golgi back to the ER. Glycosylphosphatidylinositol (GPI)-anchored proteins are secretory proteins that are attached to the cell surface of eukaryotic cells by a glycolipid moiety. Once GPI anchoring has occurred in the lumen of the endoplasmic reticulum (ER), the structure of the lipid part on the GPI anchor undergoes a remodeling process prior to ER exit. In this study, we provide evidence suggesting that the yeast p24 complex, through binding specifically to GPI-anchored proteins in an anchor-dependent manner, plays a dual role in their selective trafficking. First, the p24 complex promotes efficient ER exit of remodeled GPI-anchored proteins after concentration by connecting them with the COPII coat and thus facilitates their incorporation into vesicles. Second, it retrieves escaped, unremodeled GPI-anchored proteins from the Golgi to the ER in COPI vesicles. Therefore the p24 complex, by sensing the status of the GPI anchor, regulates GPI-anchored protein intracellular transport and coordinates this with correct anchor remodeling.