Enhancement of TBI and NTBI uptake in FRDA fibroblasts. (A) Iron quantification using the ferrozine-based colorimetric assay for control (C1-C3) and FRDA (P1-P5) fibroblasts grown under high-iron conditions (100 µM of FAC), with or without 100 µM of 2BP, for 16 hours. (B) Biotin immunoblots correlating with extent of DMT1 and ZIP14 palmitoylation in control (C1-C3) and FRDA (P1-P5) fibroblasts grown in regular medium. For each condition, the topmost panel shows palmitoylated DMT1 or ZIP14 levels (immunoprecipitated [IP]: biotin), the panel below shows the IP amount of DMT1 or ZIP14 (IP), and IP DMT1 or ZIP14 were used as a loading control. Immunoblotting quantifications of palmitoylated and steady-state levels of DMT1 and ZIP14 are given in supplemental Figure 7A-B. (C-F) Iron quantification for fibroblasts grown under high-iron (13 mM of holo-Tf [C-D] or +100 µM of FAC [E-F]) conditions for 72 hours, with or without 25 µM of CoA or 5 mM of DCA supplementation (C,E) or for 48 hours, with or without 25 µM of artesunate supplementation (D,F). Plots show mean ± standard error (n = 3). Two-way analyses of variance were used to compare untreated with treated values. *P < .05, ***P < .001. ns, nonsignificant.