Apoptosis signaling pathway

The apoptosis signaling pathway, also known as programmed cell death signaling, is a complex network that governs the orderly elimination of cells without provoking inflammation. It consists primarily of two interconnected arms: Intrinsic Pathway: Initiated by internal cellular stressors such as DNA damage or oxidative stress. This route involves mitochondrial outer membrane permeabilization regulated by pro-apoptotic and anti-apoptotic members of the Bcl‑2 protein family. Release of cytochrome c from mitochondria leads to formation of the apoptosome and activation of initiator caspase‑9 followed by effector caspases like caspase‑3. Extrinsic Pathway: Triggered by external signals through binding ligands like FasL or TNFα to their respective "death receptors" on the plasma membrane—such as Fas/CD95/APO1; TNFR1; DR3; DR4/TRAIL-R1; DR5/TRAIL-R2—which recruit adaptor proteins like FADD and activate initiator caspases (-8/-10), leading again downstream to effector caspases. Both pathways converge on executioner caspases that orchestrate cellular demolition via proteolytic cleavage events resulting in nuclear condensation, DNA fragmentation, membrane blebbing and ultimately phagocytic removal without inflammation. Dysregulation—either excessive suppression or activation—of this system underlies many diseases including cancer progression/resistance, neurodegeneration, autoimmunity, and tissue injury. Notes on Target Validity: The "Apoptosis signaling pathway" is not a single molecule/receptor, but rather an entire biological process involving numerous molecular targets—including but not limited to various receptors, enzymes (caspases), transcription factors (p53, FoxO), Bcl–2 family members, etc.. Therefore: The entry "Apoptosis signaling pathway" is too broad/vague for use as a canonical therapeutic target name—it should be replaced with specific molecules within this cascade when seeking structured data about drug targeting. If you need information about any specific component/protein/receptor within this system—for example "Caspase–3", "Bcl–2", "Fas receptor", etc.—please specify for more precise details.

Other names

Programmed cell death pathwayApoptotic pathwayCell death signaling pathway

Drugs modulate the activity of key proteins within the pathway: Activation or inhibition of caspases to induce or block apoptosis. Modulation of Bcl‑2 family proteins to shift balance toward survival or cell death. Engagement/blockade of death receptors to trigger extrinsic apoptotic signals. Restoration/enhancement of p53 function for pro-apoptotic gene expression.