Mitochondrial localization of iJC-TCRβ is essential for its ability to induce apoptosis. (A) COS-7 cells were transfected with the indicated constructs and 24 hours after transfection were stained with mouse anti-Flag antibodies followed by Alexa 488–conjugated anti–mouse antibodies. All cells were counterstained with MTR for mitochondrial detection, as indicated. Fluorescent images were taken by confocal microscopy. (B) 293 cells were transfected with the indicated constructs. At 48 hours after transfection cells were subjected to a flow cytometry cell-cycle analysis. Cells transfected with an empty pCDNA3 vector are shown (v) as indicated. Constructs are described in Figure 1A. Bar, 10 μM.