Synthesis and intracellular trafficking of Muc-1 and mucins by polarized mouse uterine epithelial cells
Synthesis and intracellular trafficking of Muc-1 and mucins by polarized mouse uterine epithelial cells
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DOI：
10.1074/jbc.271.45.28128
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发表时间：
1996-11-08
影响因子：
4.8
通讯作者：
Carson, DD
中科院分区：
文献类型：
--
作者：
Pimental, RA;Julian, J;Carson, DD
粘蛋白作为一层保护层，使上皮细胞的顶端表面不粘附各种微生物和大分子。muc1是一种跨膜黏液蛋白，在小鼠子宫上皮细胞（UEC）的顶端细胞表面表达，当UEC成为胚胎着床的受感细胞时，它会消失（Surveyor, g.a, Gendler, s.j, Pemberton， L., Das, s.k. Chakraborty， I., Julian， J., Pimental， R. a ., Wegner, c.w ., Dey, s.h .和Carson， D. D.（1995）内分泌学136,3639-3647）。在本研究中，研究了在体外极化小鼠UEC中Muc-1的组装、细胞表面表达、释放和降解动力学。黏液蛋白是野生型和muc1缺失小鼠中主要的糖缀合物，其合成、顶端表达和向体释放均为黏液蛋白。当粘蛋白被释放时，超过95%的粘蛋白被定向到根尖室。在24小时内，大约一半的细胞相关粘蛋白在根尖室中丢失。载体生物素化检测到顶端处理的细胞表面粘蛋白，并表明至少34%的这些粘蛋白在24小时内被顶端释放。这表明粘蛋白外畴的释放是UEC顶端细胞表面粘蛋白去除机制的一部分。总细胞相关粘蛋白和muc1的半衰期分别为19.5 +/- 1和16.5 +/- 0.8 h。muc1约占[H-3]氨基葡萄糖标记的细胞相关粘蛋白的10%。细胞内muc1转运动力学研究表明，从粗内质网到高尔基体的转运时间为21 +/- 15分钟，从高尔基体到细胞表面的转运时间为111 +/- 28分钟。总的来说，这些研究首次全面描述了极化细胞对muc1和粘蛋白的成熟、代谢和释放，并确定了UEC表达的粘蛋白的主要代谢命运。正常的代谢过程似乎足以解释在UEC向接受状态转变过程中muc1蛋白的去除。
Mucins function as a protective layer rendering the apical surface of epithelial cells nonadhesive to a variety of microorganisms and macromolecules. Muc-1 is a transmembrane mucin expressed at the apical cell surface of mouse uterine epithelial cells (UEC) that disappears as UEC become receptive for embryo implantation (Surveyor, G. A., Gendler, S. J., Pemberton, L., Das, S. K. Chakraborty, I., Julian, J., Pimental, R. A., Wegner, C. W., Dey, S. H., and Carson, D. D. (1995) Endocrinology 136, 3639-3647). In the present study, the kinetics of Muc-1 assembly, cell surface expression, release, and degradation were examined in polarized mouse UEC in vitro. Mucins were identified as the predominant glycoconjugates synthesized, apically expressed, and vectorially released in both wild-type and Muc-1 null mice. When mucins were released, greater than 95% were directed to the apical compartment. Approximately half of the cell-associated mucins lost during a 24-h period were found in the apical compartment. Vectorial biotinylation detected apically disposed, cell-surface mucin and indicated that at least 34% of these mucins are released apically within 24 h. This suggests that release of mucin ectodomains is part of the mechanism of mucin removal from the apical cell surface of UEC. The half-lives of total cell-associated mucins and Muc-1 were 19.5 +/- 1 and 16.5 +/- 0.8 h, respectively. Muc-1 represented approximately 10% of the [H-3]glucosamine-labeled, cell-associated mucins. Studies of the kinetics of intracellular transport of Muc-1 indicated transit times of 21 +/- 15 min from the rough endoplasmic reticulum to Golgi apparatus and 111 +/- 28 min from the Golgi apparatus to the cell surface. Collectively, these studies provide the first comprehensive description of Muc-1 and mucin maturation, metabolism, and release by polarized cells, as well as defining a major metabolic fate for mucins expressed by UEC. Normal metabolic processing appears to be sufficient to account for the removal of Muc-1 protein during the transition of UEC to a receptive state.