Intracellular control of apoptosis refers to the regulatory mechanisms within cells that govern the process of programmed cell death. Intracellular control of apoptosis is primarily regulated via the intrinsic (or mitochondrial) pathway and by the Bcl-2 family of proteins. Anti-apoptotic members of this family, such as Bcl-2 and Bcl-xL, promote cell survival by inhibiting the release of cytochrome c from mitochondria. Pro-apoptotic members, including Bax and Bak, promote apoptosis by forming channels in the outer mitochondrial membrane, leading to cytochrome c release. Cytochrome c then triggers the formation of the apoptosome, which activates caspases, the key executioners of apoptosis. Intracellular damage and negative regulators are known to be involved in either triggering or inhibiting apoptosis. Endoplasmic Reticulum (ER) stress, caused by the accumulation of misfolded proteins or disrupted calcium homeostasis is one such initiator. The unfolded protein response (UPR) is activated to restore ER homeostasis. However, if the stress is severe or prolonged, the UPR can switch from pro-survival to pro-apoptotic signalling, involving activation of CHOP (C/EBP homologous protein) and caspase-12, leading to apoptosis. Inhibitors of Apoptosis Proteins (IAPs) are a family of proteins that can inhibit caspase activity and suppress apoptosis. IAPs can directly bind to caspases, particularly caspase-3 and caspase-7, preventing their activation and subsequent apoptotic signalling. IAPs can also interact with various other apoptotic regulators, such as cytochrome c itself and the apoptosis protease-activating factor 1 (Apaf-1). These interactions disrupt the formation of the apoptosome, the complex required for caspase activation during apoptosis. Alternatively, Some IAPs, such as cellular IAPs (cIAPs), possess a RING finger domain that allows them to function as E3 ubiquitin ligases allowing them to ubiquitinate specific pro-apoptotic proteins, such as caspase-3, caspase-7, and the second mitochondria-derived activator of caspases (Smac), targeting them for proteasomal degradation. Finally, certain IAPs, such as cIAPs, can modulate the nuclear factor-kappa B (NF-κB) signalling pathway. By regulating NF-κB signalling, IAPs can indirectly inhibit apoptosis. The balance between IAPs and pro-apoptotic proteins ultimately determines the cell's susceptibility to apoptosis. Another intracellular initiator of apoptosis in cells involves the activation of the p53 tumour suppressor protein. p53 plays a crucial role in the cellular response to DNA damage and can either induce cell cycle arrest to allow DNA repair, or initiate apoptosis if the DNA damage is irreparable. p53 promotes apoptosis by transcriptionally activating several pro-apoptotic genes, such as Bax and PUMA, or by inhibiting anti-apoptotic proteins, such as Bcl-2. The inhibition of Bcl-2 by p53 occurs through several mechanisms, including transcriptional regulation whereby p53 directly binds to the promoter region of the Bcl-2 gene and inhibits its transcription, or via disruption of protein-protein interactions whereby p53 physically interacts with Bcl-2, disrupting its binding to pro-apoptotic proteins such as Bax. We provide a wide product range of research tools for investigating intracellular control of apoptosis, including p53 antibodies, Bcl-2 antibodies, NF-kB p65 antibodies, p53 ELISA Kits, and NF-kB p65 ELISA Kits. Explore our full intracellular control of apoptosis product range below and discover more, for less. Alternatively, you can explore our Associated Proteins, p53 Pathway, and Bcl2 Family product ranges.