Figure 5.

The initial rate of MUC1 endocytosis is enhanced by altered glycosylation. (A) The rate of endocytosis of [³⁵S]MUC1 in ldlD cells, synthesized in the presence of either 1000 μM GalNAc (1000GN) with or without 100 μM Gal (G+GN), was characterized as described in MATERIALS AND METHODS and the legend to Figure 4. The mean of the percent endocytosis ± SEM for each time point for three experiments is shown. By paired Student's t test analysis, only the data at 7 min was significantly different (p = 0.015) between the two sugar conditions. Regression lines are drawn for each data set and indicate a 2.2-fold difference in the rate of endocytosis (p < 0.05). (B) A representative SDS-gel pattern for internalized [³⁵S]MUC1 from a single experiment is shown, where n = 3 at each time point.