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. Author manuscript; available in PMC: 2013 Jan 16.
Published in final edited form as: Biochim Biophys Acta. 2011 Nov 10;1823(2):484–492. doi: 10.1016/j.bbamcr.2011.11.002

Fig. 3.

Fig. 3

FDX1 knock-down leads to increased IRP2, and indications of cytosolic iron depletion. (A) FDX1 knock-downs were performed using four independent oligos and both mitochondria and cytololic aconitase activities were diminished after three or four successive transfections. Aconitase activity assay revealed reduced activity of mitochondrial and cytosolic aconitases in HeLa cells treated with FDX1 siRNA (Lanes are WT, wild-type; (–)ctrl, negative control represent cells treated with Lipofectamine 2000 reagent; oligos 1–4 represent different siRNAs of FDX1). (B) Comparison of protein expression levels between FDX1 knock-down HeLa cells and wild-type and negative control HeLa cells. At the protein expression level, western blots of cells transfected with newly designed FDX1 siRNA revealed that IRP1 and α-tubulin levels (loading control) did not significantly change, IRP2 and TfR1 protein levels increased, whereas ferritin levels decreased significantly. Results shown are representative of four independent experiments. (C) mRNA levels of IRP2, TfR1 (transferrin receptor 1) IRP1, and FPN. (D) Xanthine oxidase activity assay in the RNAi-treated cells compared with the untreated wild-type and negative control cells. (E) Lactate dehydrogenase activity assay in the RNAi-treated cells compared with the untreated wild-type and negative control cells.