Where are caspases found?

In apoptotic cells, caspases 3, 8, and 9 exist in the cytosol, while caspases 3 and 9 have been found to exist in the mitochondria. Caspase 7 exists in the microsomal fraction and caspases 2 and 3 are present in the nuclear fraction. The localization of procaspases in different portions of the cell play an important, yet still unknown role in their activation. The translocation of active caspases to other portions of the cell appear to be crucial for the generation of apoptosis.