Distribution of apo-Tf–Texas Red and Fe-Tf–Texas Red in Caco-2 cells.

Caco-2 cells grown in monolayers were incubated in the basal chamber with either 0.1 μm apo-Tf–Texas Red or 0.1 μm Fe-Tf–Texas Red for 20 minutes. The cell layers were washed and processed, and the nuclei were stained with ToPro-1 and examined by confocal microscopy as described in materials and methods. Figure 1A represents the incubation with Fe-Tf and Figure 1B the incubation with apo-Tf. In both panels, the images have been reconstructed to allow examination from a lateral perspective. The lateral view (xz) is made up by the addition of consecutive pixels in the y-axis (total of 1 μm). The nuclei are stained green. The cartoon next to each image depicts the approximate height of the cells in the reconstruction.