Baricault L, Galceran M, Ronco P M, Trugnan G, Verroust P J
Inserm U 64, Hôpital Tenon, Paris, France.
Biochem Biophys Res Commun. 1995 Jul 17;212(2):353-9. doi: 10.1006/bbrc.1995.1977.
We have previously shown the close association with endocytosis of 2 glycoproteins, gp330 and gp280, expressed within the clathrin coated intermicrovillar areas of epithelial cells lining the proximal tubule and visceral layer of the yolk sac. Exposure at 37 degrees C of yolk sac epithelial cells in the presence of antibodies to gp280 induced disruption of the early endocytic pathway whereas anti-gp330 antibodies did not. In this study, using yolk sac epithelial cells in culture, we show that, in contrast to gp330 which is processed by the Golgi enzymes before expression on the plasma membrane, gp280 follows an unusual processing pathway: indeed, although the bulk of the plasma membrane gp280 is endoglycosidase H resistant, the protein is initially targeted to the plasma membrane in an endoglycosidase H sensitive form. This implies that processing takes place mainly, if not exclusively, by recycling in the Golgi apparatus.
我们之前已经表明，在近端小管内衬上皮细胞和卵黄囊脏层的网格蛋白包被的微绒毛间区域表达的两种糖蛋白gp330和gp280与内吞作用密切相关。在存在抗gp280抗体的情况下，将卵黄囊上皮细胞置于37℃会导致早期内吞途径的破坏，而抗gp330抗体则不会。在本研究中，我们使用培养的卵黄囊上皮细胞表明，与在质膜上表达之前由高尔基体酶加工的gp330不同，gp280遵循一种不同寻常的加工途径：实际上，尽管大部分质膜gp280对内切糖苷酶H具有抗性，但该蛋白最初是以对内切糖苷酶H敏感的形式靶向质膜的。这意味着加工主要（如果不是唯一）通过在高尔基体中循环进行。
