Fucosylation of glycoproteins begins in the rough endoplasmic reticulum of mouse active thyrotrophs.
Fucosylation of glycoproteins begins in the rough endoplasmic reticulum of mouse active thyrotrophs.
复制标题
糖蛋白的岩藻糖基化始于小鼠活性促甲状腺素的粗面内质网。
DOI：
10.1089/thy.1992.2.337
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Wezeman,F
中科院分区：
文献类型：
--
作者：
Magner,J;Schluep,J;Miura,Y;Wezeman,F
我们的目的是确定糖蛋白的聚焦是否开始于活性促甲状腺激素的粗内质网（RER）。这与大多数被研究的细胞形成对比，在大多数细胞中，聚焦化通常与高尔基体有关。小鼠促甲状腺肿瘤组织用[35S]蛋氨酸孵育2、5、7、10、30和90分钟。从细胞裂解物中免疫沉淀TSH和游离α-亚基，即使在短时间内，它们对扁豆凝集素（结合具有核心焦点的低聚糖）的亲和力也显示出时间依赖性的增加。由于TSH-和游离α-亚单位-扁豆结合的开始没有20-30分钟的延迟，正如可能预期的那样，聚焦化仅在高尔基体中开始，因此似乎聚焦化开始于促甲状腺激素的内质网。取甲状腺功能正常和甲状腺功能减退小鼠垂体组织用[3H]聚焦孵育，电镜放射自显影。甲状腺功能减退小鼠的垂体有大量的“甲状腺切除细胞”，在扩张的内质网池上有40%的银颗粒。“非甲状腺切除术”细胞内质网上银颗粒较少；多数在分泌颗粒和高尔基区上方。因此，活跃的小鼠促甲状腺激素似乎将部分聚焦的亚细胞位点从高尔基体转移到内质网，这一现象可能代表了一种细胞机制，通过这种机制，TSH低聚糖结构的内分泌调节得以完成。
Our aim was to determine whether fucosylation of glycoproteins begins in the rough endoplasmic reticulum (RER) of active thyrotrophs. This would contrast with most cells studied, in which fucosylation generally is associated with the Golgi apparatus. Mouse thyrotropic tumor tissue was incubated with [35S]methionine for 2, 5, 7, 10, 30, and 90 minutes. TSH and free α-subunits were immunoprecipitated from cell lysates, and they displayed a time-dependent increase in affinity for lentil lectin (which binds oligosaccharides having core fucose), even at short times. Since no 20-30 minute lag in onset of TSH- and free α-subunit-lentil binding was appreciated, as might have been expected had fucosylation begun only in the Golgi, it appeared that fucosylation was beginning in the RER of thyrotrophs. Pituitary tissue from euthyroid and hypothyroid mice was incubated with [3H]fucose, then subjected to electron microscopic autoradiography. The pituitaries of hypothyroid mice had numerous "thyroidectomy cells," which had 40% of silver grains over dilated cisternae of RER. "Nonthyroidectomy" cells had few silver grains over RER; most were over secretory granules and Golgi areas. Thus, active mouse thyrotrophs appear to shift the subcellular site of fucosylation partially from Golgi to RER, and this phenomenon may represent one cellular mechanism whereby the endocrine regulation of the structure of TSH oligosaccharides is accomplished.