FIGURE 4.

SIP inhibits apoptosis in AIF-dependent manner. A, FACS analysis of apoptosis of AIF-depleted U2OS. AIF-depleted U2OS cells were transfected with SIP expression construct or SIP siRNA. Forty-eight hours after transfection, the cells were untreated (control) or treated with STS (6 h), labeled with annexin V-FITC and PI, and analyzed by flow cytometry. Representative cytofluorometric plots are shown. B, the knockdown efficiency of AIF. U2OS cells were transfected with three pairs of AIF siRNA. Forty-eight hours after transfection, the total cell lysates from U2OS cells were examined by Western blotting analysis of the protein expression of AIF. β-actin was used as a loading control.