Fig. 2

Alkaline-earth metal selectivity. a ⁵⁵Fe efflux from control oocytes and oocytes expressing Fpn, in the presence of extracellular calcium (2 mM) and magnesium (1 mM), the absence of extracellular calcium (–Ca²⁺_oi.e. 0 mM Ca²⁺ plus 1 mM EGTA), or the absence of extracellular magnesium (–Mg²⁺_o)i.e. 0 mM Mg²⁺ plus 1 mM EDTA) (n = 12 in each group). Two-way ANOVA: interaction (P < 0.001); within Fpn, all groups differ from one another (P ≤ 0.004). b ⁵⁵Fe efflux from control oocytes and oocytes expressing Fpn in the presence of 3 mM extracellular magnesium (+Mg²⁺), or 1 mM Mg²⁺ plus 2 mM calcium (+Ca²⁺), strontium (+Sr²⁺), or barium (+Ba²⁺) (n = 30, 39, 28, 32, 27, 36, 25, 32). Two-way ANOVA: interaction (P < 0.001). In multiple pairwise comparisons vs. control: Fpn differed from control in the case of Ca²⁺ and Sr²⁺ (P < 0.001), but not Mg²⁺ (P = 0.14) or Ba²⁺ (P = 0.082); within Fpn, all conditions differed from ‘+Ca²⁺’ (P < 0.001). Bar graphs indicate mean, SD, and individual scores