Fig. 3. Amino acids 1-37 and 38-63 of AE1-4 target a cytoplasmic tailless F_c receptor to distinct intracellular membrane compartments. MDCK cells stably expressing F_c1-37 (A-C) or F_c38-63 (D-F) were fixed and incubated with rat monoclonal antibodies specific for the F_c receptor (A and D), a mouse monoclonal antibody specific for the mannose 6-phosphate receptor (B) or a rabbit polyclonal antibody specific for furin (E). The cells were washed and incubated with donkey anti-rat IgG conjugated to lissamine (A and D), goat anti-mouse IgG conjugated to FITC (B) or donkey anti-rabbit IgG conjugated to FITC (E). The localization of fluorescently labeled proteins was visualized using a Zeiss LSM510 confocal microscope. The merged images illustrate significant overlap in the distribution of Fc 1-37 and the mannose 6-phosphate receptor (C) and Fc38-63 and furin (F). Bar in A and D, 10 µm.