Mitochondrial apoptotic pathway components

The mitochondrial apoptotic pathway, also known as the intrinsic pathway, is a fundamental mechanism of programmed cell death that integrates various internal stress signals, such as DNA damage and oxidative stress [1.3.2, 1.3.4]. This pathway is primarily regulated by the BCL-2 family of proteins, which control the integrity of the mitochondrial outer membrane; anti-apoptotic members (e.g., BCL-2, BCL-XL, MCL-1) prevent the release of pro-apoptotic factors, while pro-apoptotic members (e.g., BAX, BAK) promote mitochondrial outer membrane permeabilization (MOMP) [1.2.4, 1.3.5]. Following MOMP, apoptogenic proteins such as cytochrome c and SMAC/DIABLO are released into the cytoplasm, where cytochrome c triggers the formation of the apoptosome and the activation of caspase-9 [1.3.3, 1.3.4]. This initiates a cascade of executioner caspases (caspase-3, -6, and -7) that carry out the final stages of cell death [1.3.3]. Dysregulation of these components is a hallmark of cancer, where evasion of apoptosis leads to tumor progression and drug resistance, as well as neurodegenerative and cardiovascular diseases characterized by excessive cell loss [1.2.5, 1.3.1, 1.3.5]. The pathway's complexity offers multiple nodes for pharmacological intervention, ranging from the direct inhibition of anti-apoptotic proteins to the antagonism of endogenous caspase inhibitors. Clinical success with agents like venetoclax has validated the approach of targeting these components to overcome apoptosis resistance in hematological malignancies, while ongoing research explores their potential in solid tumors and non-oncological indications [1.2.4, 1.3.5].

Other names

Intrinsic apoptotic pathway componentsMitochondrial death pathway componentsBCL-2 family and downstream effectorsMitochondria-mediated apoptotic pathway

Modulation of the intrinsic apoptotic threshold through the inhibition of anti-apoptotic BCL-2 family proteins (BH3 mimetics), antagonism of Inhibitor of Apoptosis Proteins (IAPs) by SMAC mimetics, or direct inhibition of caspase enzymes to regulate the execution of programmed cell death [1.2.4, 1.3.5].