FIGURE 4.

¹²⁵I-HA binding and endocytosis by cells expressing multiple motif HARE CD mutants. Cells expressing EV, WT 190-HARE, or 190-HARE mutants were incubated at 37 °C in serum-free medium for 1 h, washed, incubated, and processed to quantify ¹²⁵I-HA binding at 4 °C or endocytosis at 37 °C as described in Fig. 3. A, cell surface and total cellular ¹²⁵I-HA binding are indicated for cells expressing EV (black) or 190-HARE: WT (white bars), ΔM1M2 (horizontal rectangles), ΔM1M2M4 (diagonal rectangles), ΔM1M2M3M4 (diagonal lines), Y2519A (arrowheads), or ΔM1M2M4 + Y2519A (checkerboard). B, endocytosis of ¹²⁵I-HA by cells expressing 190-HARE: WT (○), ΔM1M2 (▾), ΔM1M2M4 (▵), ΔM1M2M3M4 (▪), or EV (•). C, endocytosis of ¹²⁵I-HA by cells expressing 190-HARE: WT (○), Y2519A (▾), ΔM1M2M4 + Y2519A (▵), ΔM3 (▪), or EV (•).