Fig 1: Defective mitochondrial ISCs assembly activates mitophagy. (A) mt-Keima stable HeLa cells were transfected with siRNAs targeting ISCU, FXN, NFS1 or ISD11, or the NC siRNA. After 72 h of transfection, the cells were collected and signals from green and red channels were detected by flow cytometry. The percentage of mitophagic cells with higher red/green fluorescence was shown in the right below histograms as mean ± SEM of three experiments. ***p < 0.001. (B) Cells as in (A) were imaged with 458 nm (shown in green) or 543 nm (shown in red) light excitation using a LSM 510 Zeiss confocal microscope. Representative images are presented. Scale bar, 10 µm. (C) Graph showing the number of mt-Keima dots per cell in (B). Data represent the mean ± SEM of three independent experiments, each with >200 cells counted per condition. ***p < 0.001. (D) HeLa cells were transfected with siRNAs targeting ISCU, FXN, NFS1 or ISD11, or the NC siRNA. After 72 h of transfection, the cells were harvested for immunoblotting analysis. The relative levels of indicated bands are shown in the right histograms. Data represent the mean ± SEM of three independent experiments. (E) ATG5 stable knockdown HeLa cells and the control cells were transfected with siRNAs targeting ISCU, FXN, NFS1 or ISD11, or the NC siRNA. After 72 h of transfection, the cells were harvested for immunoblotting analysis. (F–G) HeLa cells were transfected with siRNAs targeting CIAO1 (F) or NARFL (G). After 72 h of transfection, the cells were harvested for immunoblotting. The relative levels of indicated bands are shown in the right histograms. Data represent the mean ± SEM of three independent experiments. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)