Figure 2.

Internalization of CIE and not CME cargo is sensitive to changes in glycan interactions. Antibody internalization for 30 min at 37 °C in HeLa cells after 48-h incubation with or without 10 mm GlcNAc and in the presence or absence of 100 mm lactose for MHCI (A) and CD59 (B) indicates cargo-specific effects of increasing glycan branching (due to GlcNAc treatment) and an inhibition of CIE with lactose treatment. 48-h incubation with 10 mm glucose or 1-h pretreatment with 100 mm sucrose had no significant effect on the CIE of MHCI or CD59. C, flow cytometric analysis of clathrin-mediated endocytosis of fluorescently labeled transferrin internalized over 10 min at 37 °C in HeLa cells shows that CME is unaffected by altering glycan interactions. 48-h incubation with or without 2 μg/ml swainsonine led to similar changes in internalization as lactose treatment for MHCI (D), CD59 (E), and transferrin (F). At least three independent experiments were carried out with data expressed as mean ± S.D. (error bars). *, p < 0.05.