Figure 3.
Postendocytic fate of basolaterally internalized Tf in RhoAWT, RhoAV14, or RhoAN19 cells. [125I]Tf was internalized from the basolateral pole of the cell for 45 min at 37°C. The cells were then washed at 4°C and warmed for 2.5 min at 37°C to allow for receptor internalization, and the postendocytic fate of internalized [125I]Tf was determined in a 120-min chase at 37°C. The percentage of ligand released basolaterally (recycled) or released apically (transcytosed) in RhoAWT (A), RhoAV14 (B), or RhoAN19 (C) cells is shown. Values for degradation were as follows: RhoAWT + DC, 1.9 ± 0.2%; RhoAWT − DC, 1.9 ± 0.1%; RhoAV14 + DC, 1.9 ± 0.4%; RhoAV14 + 5 pg/ml DC, 2.6 ± 0.2%; RhoAN19 + DC, 2.6 ± 0.3%; RhoAN19 − DC, 3.0 ± 0.2%. Values for ligand remaining cell associated were as follows: RhoAWT + DC, 1.5 ± 0.2%; RhoAWT − DC, 1.4 ± 0.1%; RhoAV14 + DC, 2.3 ± 0.5%; RhoAV14 + 5 pg/ml DC, 10.3 ± 2.1%; RhoAN19 + DC, 3.1 ± 0.3%; RhoAN19 − DC, 3.0 ± 0.8%. Values (mean ± SD; n = 3) are from a representative experiment. (A and C) ■, +DC, transcytosed; ●, +DC, recycled; ▴, −DC, transcytosed; ♦, −DC, recycled. (B) ■, +DC, transcytosed; ●, +DC, recycled; ▴, 5 pg/ml DC, transcytosed; ♦, 5 pg/ml DC, recycled.