Snider M D, Rogers O C
J Cell Biol. 1986 Jul;103(1):265-75. doi: 10.1083/jcb.103.1.265.
The recycling of cellular glycoproteins to the site of Golgi mannosidase I, an enzyme of asparagine-linked oligosaccharide synthesis, was studied in K562 human erythroleukemia cells. Cells were metabolically labeled in the presence of deoxymannojirimycin, a reversible inhibitor of Golgi mannosidase I. This generates glycoproteins with immature oligosaccharides in their normal locations. Transport to the mannosidase I compartment was then assessed by testing for the conversion of oligosaccharides into mature forms during reculture without deoxymannojirimycin. Transferrin receptor (TfR) was acted on by mannosidase I during reculture, suggesting that it returned to the region of the Golgi complex where this enzyme resides. The slow rate of this transport (t1/2 greater than 6 h) implies that it is probably different than TfR movement during transferrin internalization (t1/2 = 10-20 min) and TfR transport to the sialyltransferase compartment in the Golgi complex (t1/2 = 2-3 h) (Snider, M. D., and O. C. Rogers, 1985, J. Cell Biol., 100:826-834). The total cell glycoprotein pool was also transported to the mannosidase I compartment with a half-time of 4 h. Because this transport is 5-10 times faster than the rate of de novo glycoprotein synthesis in these cells, it is likely that most of the glycoprotein traffic through the Golgi complex is composed of recycling molecules.
在K562人红白血病细胞中研究了细胞糖蛋白向高尔基体甘露糖苷酶I（一种天冬酰胺连接寡糖合成酶）所在部位的再循环。在脱氧甘露基野尻霉素（高尔基体甘露糖苷酶I的一种可逆抑制剂）存在的情况下对细胞进行代谢标记。这会产生在其正常位置带有未成熟寡糖的糖蛋白。然后通过在无脱氧甘露基野尻霉素的再培养过程中检测寡糖向成熟形式的转化来评估向甘露糖苷酶I区室的转运。再培养过程中，转铁蛋白受体（TfR）受到甘露糖苷酶I的作用，这表明它回到了该酶所在的高尔基体复合体区域。这种转运的缓慢速率（半衰期大于6小时）意味着它可能与转铁蛋白内化过程中TfR的移动（半衰期 = 10 - 20分钟）以及TfR向高尔基体复合体中唾液酸转移酶区室的转运（半衰期 = 2 - 3小时）不同（斯奈德，M. D.，和O. C. 罗杰斯，1985年，《细胞生物学杂志》，100:826 - 834）。总的细胞糖蛋白库也以4小时的半衰期被转运到甘露糖苷酶I区室。由于这种转运比这些细胞中糖蛋白从头合成的速率快5 - 10倍，很可能通过高尔基体复合体的大部分糖蛋白运输是由再循环分子组成的。
