Figure 1.

Uptake of ferric citrate into the cytosol of RAW cells. Effect of human serum albumin, inhibitors of endocytosis and impermeant iron chelators. RAW cells labeled in the cytosol with CALG via its AM precursor were followed for up to 1 h by epifluorescence microscopy while perfused in DMEM-HEPES supplemented with ferric citrate only (Fe:citrate10: 30 μM) (FC), or together with 50 μM human serum albumin (FC+HSA) and the indicated substances: nocodazole (N=30 μM), ML-9 (M=100 μM)(FC+HSA+N+M), cytochalasin D (cyD= 100 μM) (FC+HSA+CyD), and hydroxyethyl-starch-DFO (FC+HSA+HES-DFO 50 μM). Systems without added ferric citrate were HSA alone (50 μM) (HSA), HSA with nocodazole (N=30 μM) and ML-9 (M=100 μM)(HSA+N+M) and HSA with hydroxyethyl-starch-DFO (HSA+HES-DFO 50 μM). All incubations and perfusions were carried out at 37°C. The pictures show snapshots of the same field taken at 0 at 40 min, and the graph shows the mean fluorescence quenching (FQ) of each field (analyzed with NIH Image J; National Institutes of Health, Bethesda, MD, USA) normalized to the initial fluorescence intensity (control cells).