Iron-dependent modulation of IRP1 activity in erythroid versus nonerythroid cells.

IRE/IRP EMSAs were performed with cytoplasmic extracts of the following erythroid and nonerythroid cells: SCF progenitors (SCF), c-Kit progenitors (c-Kit), HD3E22 erythroblasts (HD3), MC29-HD11 macrophages (MC29), v-Ski progenitors (v-Ski), and leghorn male hepatocytes (LMH). The cells were cultured in the presence of 1 mg/mL Tf (Tf), 20 μg/mL FAC (FAC), 50 μM DFO (DFO) or in the absence of any additional iron source (no Fe). Apparent (−2-ME) and total IRP1 (+2-ME) activities were quantified as described in the legend of Figure 2 and in “Materials and methods” and are expressed in relative units, which are directly comparable within this data set.