Human MUC5AC mucin dimerizes in the rough endoplasmic reticulum, similarly to the MUC2 mucin
Human MUC5AC mucin dimerizes in the rough endoplasmic reticulum, similarly to the MUC2 mucin
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DOI：
10.1042/bj3350381
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发表时间：
1998-10-15
影响因子：
4.1
通讯作者：
Hansson, GC
中科院分区：
文献类型：
--
作者：
Asker, N;Axelsson, MAB;Hansson, GC
对人 MUC5AC 粘蛋白的生物合成研究是通过使用仅识别结肠腺癌细胞系 LS 174T 中非 O-糖基化的阿朴粘蛋白的抗血清进行免疫沉淀来进行的。脉冲追踪研究和亚细胞分级分离表明，MUC5AC 在生物合成开始后 15 分钟内在粗面内质网中形成二聚体。没有鉴定出大于二聚体的非O-糖基化物种。二聚化是N-糖基化依赖性的，因为衣霉素处理显着降低了二聚化率。当将 MUC5AC 载脂蛋白的生物合成与同样在 LS 174T 细胞系中产生的 MUC2 载脂蛋白的生物合成进行比较时，两种载脂蛋白在抑制和不抑制 N-糖基化的情况下，在二聚化速率方面以相似的方式组装。尽管认为参与粘蛋白二聚化的C末端半胱氨酸残基位置存在广泛的序列相似性，但在人MUC5AC和MUC2脱辅基粘蛋白之间没有观察到异二聚化。
Biosynthetic studies on the human MUC5AC mucin were performed by immunoprecipitations with antisera recognizing only the non-O-glycosylated apomucin in the colon adenocarcinoma cell line LS 174T. Pulse-chase studies and subcellular fractionations showed that MUC5AC formed dimers in the rough endoplasmic reticulum within 15 min of the initiation of biosynthesis. No non-O-glycosylated species larger than dimers were identified. The dimerization was N-glycosylation-dependent, because tunicamycin treatment significantly lowered the rate of dimerization. When the biosynthesis of MUC5AC apomucin was compared with that of MUC2 apomucin, also produced in the LS 174T cell line, both apomucins were assembled in similar ways with respect to their rates of dimerization with and without inhibition of N-glycosylation. No heterodimerization was observed between the human MUC5AC and the MUC2 apomucins despite the extensive sequence similarities in the positions of the cysteine residues in the C-termini proposed to be involved in mucin dimerization.