FIG. 6.

Brefeldin A induces mitochondrial translocation of c-Abl. (A) Rat1 cells were treated with 10 μg of brefeldin A per ml for 8 h. Cytoplasmic and nuclear fractions were subjected to immunoblotting (IB) with anti-c-Abl, anti-β-actin, anti-PCNA, or anticalreticulin. (B) Rat1 cells were treated with 10 μg of brefeldin A per ml for the indicated times. Mitochondrial fractions were subjected to immunoblotting with anti-c-Abl or anti-HSP60. The signal intensities of c-Abl protein were compared to that of the control. (C) Rat1 cells were treated with 10 μg of brefeldin A per ml and harvested at the indicated times. Mitochondrial fractions were subjected to immunoprecipitation (IP) with anti-c-Abl. The precipitates were analyzed in a c-Abl kinase assay using GST-Crk(120–225) as the substrate or subjected to immunoblotting with anti-c-Abl. The signal intensities of c-Abl activity and protein were compared to that of the control. (D) The increases in mitochondrial c-Abl protein (solid bars) and activity (open bars) are expressed as the means plus standard deviations obtained from three separate experiments.