Figure 7.

Mitochondrial release of survivin during apoptosis. (A) Effect on cytochrome c release. INS-1 cells stably transfected with MT-GFP or MT-S were treated with staurosporine, harvested at the indicated time intervals, and analyzed by immunoblotting. (B) Fluorescence microscopy. INS-1/MT-S cells were treated with staurosporine and analyzed for cytosolic redistribution of GFP. (C) Single-cell analysis. Areas corresponding to mitochondria (yellow squares) or cytosol (gray circles) were quantitatively analyzed for changes in fluorescence distribution before (None) or after staurosporine treatment (left panel). Right panel: Quantification of single-cell analysis. Changes in fluorescence intensity in individual mitochondrial or cytosolic areas were analyzed in the presence or absence of staurosporine treatment. Data represent an average of 16 individual determinations for mitochondrial areas and 14 individual determinations for cytosolic areas. (D) Time course of mitochondrial release of survivin during cell death. INS-1/MT-S cells were treated with staurosporine, and isolated mitochondrial or cytosolic fractions were analyzed at the indicated time intervals by immunoblotting. Right panel: Densitometric quantification of time-dependent depletion of mitochondrial survivin in response to staurosporine.