cis-Golgi 中 N-糖基化的修剪和延伸
中文名称
通路描述
糖蛋白转运至 cis-Golgi 后，N-糖基化途径发生分叉。一些 N-糖链可以移动到分泌途径的后续步骤而不进行进一步修饰，或者通过移除几个甘露糖残基（寡甘露糖途径）来实现。在酵母和其他单细胞生物中，会添加一系列甘露糖残基（高甘露糖途径）。这种修饰的存在是酵母中生产药物的一大障碍，因为必须抑制或修改高甘露糖途径以避免高甘露糖异种糖链的存在。N-糖基化的第一个修饰步骤是由三种甘露糖苷酶之一进行的，它们可修剪多达四个甘露糖残基。此外，如果糖蛋白尚未进入 Calnexin/Calreticulin 循环，或者在 ER 中其葡萄糖残基尚未被修剪，它们可以通过由酶 Endomannosidase I 催化的替代途径进入主要途径（Schachter, 2000; Stanley et al, 2009）。
英文描述
N-glycan trimming and elongation in the cis-Golgi After the transport of the glycoprotein to the cis-Golgi, the pathway of N-glycosylation bifurcates. Some N-glycans can be moved to subsequent steps of the secretory pathway without further modifications, or alternatively, with the removal of a few mannoses (Oligo Mannoses pathway). In yeast and other unicellular species, a series of mannose residues are added (High Mannoses pathway). The presence of this modification is a major obstacle to the production of pharmaceutical drugs in yeast, where the HighMannose pathway must be inhibited or modified in order to avoid the presence of high mannose xenoglycans.
The first N-glycan modification step is the trimming of up to four mannoses by one of three mannosidase enzymes. Moreover, Glycoproteins that have not entered in the Calnexin/Calreticulin cycle or that have not had their glucose residues trimmed earlier in the ER, can enter the main pathway here due to the existence to an alternative route catalyzed by the enzyme Endomannosidase I (Schachter, 2000; Stanley et al, 2009)
The first N-glycan modification step is the trimming of up to four mannoses by one of three mannosidase enzymes. Moreover, Glycoproteins that have not entered in the Calnexin/Calreticulin cycle or that have not had their glucose residues trimmed earlier in the ER, can enter the main pathway here due to the existence to an alternative route catalyzed by the enzyme Endomannosidase I (Schachter, 2000; Stanley et al, 2009)
所含基因
2 个基因