FIGURE 6.

Influence of AZIN2 modifications on polyamine uptake by COS7 cells. A, scheme of the AZIN2 constructions. The FLAG epitope was added to the N terminus of AZIN2, and the streptavidin-binding peptide (SBP) or the green fluorescent protein (GFP) were fused to the C terminus of AZIN2 by the appropriate subcloning of AZIN2 in tagged plasmids (see “Experimental Procedures”). B, cells were transfected with the wild type AZIN2 or the different constructs generated. The comparison of protein levels of AZIN1-FLAG and AZIN2-FLAG, measured by Western blot using an anti-FLAG antibody, is shown above their respective columns. Loading controls were performed using anti Erk2 antibody (data not shown). Control cells (C) were transfected with the empty vector. Polyamine uptake assays were carried out using 2 μm ¹⁴C-labeled putrescine for 30 min. Data are shown as mean ± S.E. of triplicate determinations.