Fig. 5.

ABCB8 modulation alters mitochondrial iron export. (A) Western blot of HEK293 cells treated with control and ABCB8 siRNA. (B) Flow cytometry analysis of rhodamine 123-stained mitochondria revealed no difference in mitochondrial membrane potential between ABCB8 and control siRNA treated HEK293 cells (n = 3). Unstained mitochondria were used as a blank. (C) Export of ⁵⁵Fe was reduced in isolated mitochondria from ABCB8 siRNA-treated cells compared with control siRNA-treated cells. Radioactivity in the soluble fraction was measured and normalized to mitochondrial protein and total cellular radioactivity (n = 3). (D) Export of ⁵⁵Fe was increased in isolated mitochondria from ABCB8 adenovirus-transduced cells compared with GFP (n = 4). (E) ABCB8 siRNA treatment did not alter ³²P export, suggesting the effect on ⁵⁵Fe export is specific to ABCB8 modulation (n = 3). Data are presented as mean ± SEM (*P < 0.05).