Fig. 4. Co-localization of IRP1 with the ER marker calnexin in iron-depleted or iron-loaded SW1088 cells. These are representative confocal images of SW1088 cells that were exposed to iron (A-D) or to the iron chelator DFO (E-H) for 72 hours prior to fixation. Following fixation the cells were stained with DAPI (blue) to visualize the nucleus and with an IRP1 antibody (green in B and F) or the ER marker calnexin (red in C and G). The merged images are shown in D and H. The co-localization of IRP1 and the ER are indicated by yellow. Treatment with iron or an iron chelator did not result in changes in IRP1 distribution that could be identified microscopically.