Stieger B, Matter K, Baur B, Bucher K, Höchli M, Hauri H P
Department of Pharmacology, University of Basel, Switzerland.
J Cell Biol. 1988 Jun;106(6):1853-61. doi: 10.1083/jcb.106.6.1853.
Novel subcellular fractionation procedures and pulse-chase techniques were used to study the intracellular transport of the microvillar membrane hydrolases sucrase-isomaltase and dipeptidylpeptidase IV in the differentiated colon adenocarcinoma cell line Caco-2. The overall rate of transport to the cell surface was two fold faster for dipeptidylpeptidase IV than for sucrase-isomaltase, while no significant differences were observed in transport rates from the site of complex glycosylation to the brush border. The delayed arrival of sucrase-isomaltase in the compartment where complex glycosylation occurs was only in part due to exit from the endoplasmic reticulum. A major slow-down could be ascribed to maturation in and transit of this enzyme through the Golgi apparatus. These results suggest that the observed asynchronism is due to more than one rate-limiting step along the rough endoplasmic reticulum to trans-Golgi pathway.
采用新型亚细胞分级分离程序和脉冲追踪技术，研究了分化型结肠腺癌细胞系Caco-2中微绒毛膜水解酶蔗糖酶-异麦芽糖酶和二肽基肽酶IV的细胞内转运。二肽基肽酶IV转运至细胞表面的总体速率比蔗糖酶-异麦芽糖酶快两倍，而从复杂糖基化位点到刷状缘的转运速率未观察到显著差异。蔗糖酶-异麦芽糖酶在发生复杂糖基化的区室中延迟到达，这仅部分归因于其从内质网排出。主要的减慢可归因于该酶在高尔基体中的成熟和转运。这些结果表明，观察到的不同步是由于沿粗面内质网到反式高尔基体途径存在多个限速步骤。
