DETECTION OF PRO-CASPASE-3 IN CYTOSOL AND MITOCHONDRIA OF VARIOUS TISSUES

Caspases are a family of cysteine proteases of critical importance in the apoptotic cell death process. They are normally present as zymogen s (pro-caspases) in the cytoplasm of vertebrate and other organisms. I n this study me have shown that pro-caspase-3 is localized to cytosol and mitochondria of various rat tissues (brain, heart, kidney, liver, spleen and thymus). Although the majority of pro-caspase-3 was localiz ed in the cytosol, the amount of mitochondrial pro-caspase-3 was signi ficant. The ratio of cytosolic and mitochondrial pools of pro-caspase- 3 appeared to vary between different tissues. The higher amount of mit ochondrial pro-caspase-3 was found in thymus and spleen, i,e. tissues in which spontaneous apoptosis plays an important role, Our findings p rovide further support for mitochondrial localization of pro-caspase-3 and the critical role of this organelle in apoptosis, (C) 1998 Federa tion of European Biochemical Societies.