Caspase-3 is a key protease involved in apoptosis, playing a critical role in various cellular processes. It is activated through pathways that may be dependent or independent of mitochondrial cytochrome c release and caspase-9 function. Caspase-3 is essential for normal brain development and is important or essential in other apoptotic scenarios in a tissue-, cell type- or death stimulus-specific manner. It is required for some typical hallmarks of apoptosis, including apoptotic chromatin condensation and DNA fragmentation in all cell types examined. However, caspase-3 may also function before or at the stage when commitment to loss of cell viability is made. Caspase-3 is required for some, but not all, cell deaths and distinct apoptotic processes. Caspase-3-knockout mice show a striking phenotype with skull defects and ectopic masses of supernumerary cells, indicating that caspase-3 acts in a tissue-selective manner. Caspase-3 is important for apoptosis in peripheral T cells but is dispensable during T and B cell differentiation. Caspase-3-defective embryonic stem cells are resistant to certain apoptotic stimuli but sensitive to others. Caspase-3 is essential for cell death in some scenarios but not all, and is required for certain morphological changes associated with apoptosis. Caspase-3 is involved in the cleavage of various proteins, including α-fodrin, gelsolin, and ICAD/DFF-45, which contribute to the morphological changes of apoptosis. The cleavage of these proteins is essential for certain apoptotic events, but not all. Caspase-3 is also involved in the release of cytochrome c from mitochondria, which is a key step in the activation of caspase-3. However, caspase-3 can also be activated independently of mitochondrial cytochrome c release. Caspase-3 is a critical upstream activator of caspase-3 in some pathways, but not all. The absence of caspase-3 leads to impaired apoptosis in certain cell types, but not in others. The role of caspase-3 in apoptosis is complex and varies depending on the cell type and the specific apoptotic stimulus. Caspase-3 is essential for certain processes associated with the dismantling of the cell and the formation of apoptotic bodies, but it may also function before or at the stage when commitment to loss of cell viability is made.Caspase-3 is a key protease involved in apoptosis, playing a critical role in various cellular processes. It is activated through pathways that may be dependent or independent of mitochondrial cytochrome c release and caspase-9 function. Caspase-3 is essential for normal brain development and is important or essential in other apoptotic scenarios in a tissue-, cell type- or death stimulus-specific manner. It is required for some typical hallmarks of apoptosis, including apoptotic chromatin condensation and DNA fragmentation in all cell types examined. However, caspase-3 may also function before or at the stage when commitment to loss of cell viability is made. Caspase-3 is required for some, but not all, cell deaths and distinct apoptotic processes. Caspase-3-knockout mice show a striking phenotype with skull defects and ectopic masses of supernumerary cells, indicating that caspase-3 acts in a tissue-selective manner. Caspase-3 is important for apoptosis in peripheral T cells but is dispensable during T and B cell differentiation. Caspase-3-defective embryonic stem cells are resistant to certain apoptotic stimuli but sensitive to others. Caspase-3 is essential for cell death in some scenarios but not all, and is required for certain morphological changes associated with apoptosis. Caspase-3 is involved in the cleavage of various proteins, including α-fodrin, gelsolin, and ICAD/DFF-45, which contribute to the morphological changes of apoptosis. The cleavage of these proteins is essential for certain apoptotic events, but not all. Caspase-3 is also involved in the release of cytochrome c from mitochondria, which is a key step in the activation of caspase-3. However, caspase-3 can also be activated independently of mitochondrial cytochrome c release. Caspase-3 is a critical upstream activator of caspase-3 in some pathways, but not all. The absence of caspase-3 leads to impaired apoptosis in certain cell types, but not in others. The role of caspase-3 in apoptosis is complex and varies depending on the cell type and the specific apoptotic stimulus. Caspase-3 is essential for certain processes associated with the dismantling of the cell and the formation of apoptotic bodies, but it may also function before or at the stage when commitment to loss of cell viability is made.