Apoptosis, or programmed cell death, is a genetically controlled process that involves the loss of viability, cytoplasmic boiling, chromatin condensation, and DNA fragmentation. The identification of genes that control cell death and the understanding of their roles in development and disease have driven research into apoptosis. Regulation of cell death is crucial for normal development and defense against viral infections and cancer. The Bcl-2 family of proteins, which includes Bcl-2, Bcl-xL, Mcl-1, Bax, Bak, and others, plays a central role in regulating apoptosis. These proteins can act as inhibitors or activators of apoptosis, and their interactions with other proteins are essential for controlling the outcome of apoptosis. For example, Bcl-2 and Bcl-xL inhibit apoptosis, while Bax and Bak can promote apoptosis. The Bcl-2 family members interact with each other and with non-family proteins, such as R-ras and Bag-1, to regulate apoptosis. Other regulators of apoptosis include the baculovirus p35 and iap genes, which inhibit apoptosis and enhance virus production. The tumor suppressor genes p53 and Rb also regulate apoptosis, with p53 acting as a transcription factor to induce apoptosis and Rb controlling cell cycle progression and DNA synthesis. ICE-related cysteine proteases, such as CPP32, are involved in apoptosis by cleaving specific substrates, including poly(ADP) ribose polymerase and nuclear lamins. The pathways to control apoptosis are complex and involve interactions between various proteins and signaling pathways, with the outcome depending on the ratio of pro-apoptotic to anti-apoptotic factors.Apoptosis, or programmed cell death, is a genetically controlled process that involves the loss of viability, cytoplasmic boiling, chromatin condensation, and DNA fragmentation. The identification of genes that control cell death and the understanding of their roles in development and disease have driven research into apoptosis. Regulation of cell death is crucial for normal development and defense against viral infections and cancer. The Bcl-2 family of proteins, which includes Bcl-2, Bcl-xL, Mcl-1, Bax, Bak, and others, plays a central role in regulating apoptosis. These proteins can act as inhibitors or activators of apoptosis, and their interactions with other proteins are essential for controlling the outcome of apoptosis. For example, Bcl-2 and Bcl-xL inhibit apoptosis, while Bax and Bak can promote apoptosis. The Bcl-2 family members interact with each other and with non-family proteins, such as R-ras and Bag-1, to regulate apoptosis. Other regulators of apoptosis include the baculovirus p35 and iap genes, which inhibit apoptosis and enhance virus production. The tumor suppressor genes p53 and Rb also regulate apoptosis, with p53 acting as a transcription factor to induce apoptosis and Rb controlling cell cycle progression and DNA synthesis. ICE-related cysteine proteases, such as CPP32, are involved in apoptosis by cleaving specific substrates, including poly(ADP) ribose polymerase and nuclear lamins. The pathways to control apoptosis are complex and involve interactions between various proteins and signaling pathways, with the outcome depending on the ratio of pro-apoptotic to anti-apoptotic factors.