This study investigates the roles of caspases 3 and 7 in apoptosis, focusing on their involvement in mitochondrial events. The researchers generated mice deficient in both caspases and observed that these mice died shortly after birth with defects in cardiac development. Fibroblasts lacking both enzymes showed resistance to apoptosis, preserved mitochondrial membrane potential, and defective nuclear translocation of apoptosis-inducing factor (AIF). Early apoptotic events such as Bax translocation and cytochrome c release were also delayed. Mitochondria play a central role in apoptosis, with mitochondrial outer membrane permeabilization (MOMP) leading to the release of proapoptotic factors like cytochrome c and AIF. The study shows that caspases 3 and 7 are critical mediators of mitochondrial events in apoptosis. While caspase 3 is involved in DNA fragmentation and morphological changes of apoptosis, caspase 7 plays a more significant role in the loss of cellular viability. The study also found that DKO mice (deficient in both caspases 3 and 7) showed increased viability after death-receptor pathway stimulation, suggesting that caspases 3 and 7 are not essential for thymocyte selection. However, they are crucial for maintaining viability. The study further shows that caspases 3 and 7 are key mediators of the loss of mitochondrial membrane potential (ΔΨm) during apoptosis. The results indicate that caspases 3 and 7 have overlapping but distinct roles in apoptosis. Caspase 3 is primarily involved in DNA fragmentation and morphological changes, while caspase 7 is more important for the loss of cellular viability. The study also highlights the importance of mitochondria in cell death, with ΔΨm being critical for normal mitochondrial function and its loss associated with apoptosis. The findings suggest that caspases 3 and 7 are essential for the proper functioning of mitochondrial events in apoptosis.This study investigates the roles of caspases 3 and 7 in apoptosis, focusing on their involvement in mitochondrial events. The researchers generated mice deficient in both caspases and observed that these mice died shortly after birth with defects in cardiac development. Fibroblasts lacking both enzymes showed resistance to apoptosis, preserved mitochondrial membrane potential, and defective nuclear translocation of apoptosis-inducing factor (AIF). Early apoptotic events such as Bax translocation and cytochrome c release were also delayed. Mitochondria play a central role in apoptosis, with mitochondrial outer membrane permeabilization (MOMP) leading to the release of proapoptotic factors like cytochrome c and AIF. The study shows that caspases 3 and 7 are critical mediators of mitochondrial events in apoptosis. While caspase 3 is involved in DNA fragmentation and morphological changes of apoptosis, caspase 7 plays a more significant role in the loss of cellular viability. The study also found that DKO mice (deficient in both caspases 3 and 7) showed increased viability after death-receptor pathway stimulation, suggesting that caspases 3 and 7 are not essential for thymocyte selection. However, they are crucial for maintaining viability. The study further shows that caspases 3 and 7 are key mediators of the loss of mitochondrial membrane potential (ΔΨm) during apoptosis. The results indicate that caspases 3 and 7 have overlapping but distinct roles in apoptosis. Caspase 3 is primarily involved in DNA fragmentation and morphological changes, while caspase 7 is more important for the loss of cellular viability. The study also highlights the importance of mitochondria in cell death, with ΔΨm being critical for normal mitochondrial function and its loss associated with apoptosis. The findings suggest that caspases 3 and 7 are essential for the proper functioning of mitochondrial events in apoptosis.