Figure 7.

Transferrin internalization and recycling in Eph4 cells. Eph4 cells were plated on plastic dishes: when 80% confluent, half of the wells were induced with interferon. Transferrin internalization and recycling in Eph4 cells harboring Mx-rab17N132I (A and B) were measured as outlined in Materials and Methods, minus (□) and plus (•) interferon induction. In C and D Eph4 cells harboring Mx-rab17N132I were grown on filter supports, half of the filters were induced with interferon and transferrin was prebound to the basolateral surface. Transferrin recycled to the basolateral medium and internal values, minus (□) and plus (•) interferon induction, were measured. In E Parental Eph4 cells and Eph4 cells harboring Mx-rab17 WT, Mx-rab17Q77L, and Mx-rab17N132I were grown on filter supports and half of the filters were induced with interferon. Transferrin was continuously internalized from the basolateral surface for 90 min at 37°C. Then the cells were rapidly cooled on ice, the apical media collected, and measured as previously described (see Materials and Methods). The given values represent the mean of duplicate samples expressed relative to the same cell line without interferon induction; the experiments were repeated three times with similar results.