Molecular Classification
Other (describes a biological pathway, not a molecule)
Other Names
Intrinsic apoptosis pathway, Mitochondrial apoptosis pathway, Intrinsic pathway of apoptosis, Mitochondria-mediated apoptosis
Disease Roles
CancerNeurodegenerative diseaseInfection

Apoptosis induction via mitochondrial pathway Overview

The mitochondrial pathway of apoptosis, also called the intrinsic apoptosis pathway, describes a regulated process that leads to programmed cell death in response to intracellular stress signals such as DNA damage, oxidative stress, or cytokine withdrawal. Central to this pathway is the permeabilization of the mitochondrial outer membrane (MOMP), controlled by the opposing actions of pro-apoptotic (e.g., BAX, BAK) and anti-apoptotic (e.g., BCL-2, BCL-xL, MCL-1) members of the BCL-2 protein family. Upon MOMP, mitochondrial proteins like cytochrome c and SMAC/DIABLO are released into the cytosol. Cytochrome c binds Apaf-1, forming the apoptosome and activating caspase-9, which in turn activates effector caspases such as caspase-3, irreversibly committing the cell to apoptosis. Dysregulation of this pathway (particularly by overexpression of anti-apoptotic BCL-2 family members) is implicated in cancer cell survival, and targeted drugs ("BH3 mimetics" like venetoclax) have been developed to restore effective apoptosis by antagonizing anti-apoptotic BCL-2 proteins[1][2][4][5][7]. The key druggable molecular targets in this pathway are protein families—not the mitochondrial pathway itself. Examples include BCL-2, BCL-xL, MCL-1 (anti-apoptotic), and BAX, BAK (pro-apoptotic). The entry as provided names a process/pathway, not a molecule; therefore, it should be marked as "incorrect" for structured therapeutic targeting, but detailed pathway and drug information is included above for context[1][2][4][5][7].

Mechanism of Action

Induction of mitochondrial outer membrane permeabilization (MOMP), Inhibition of anti-apoptotic BCL-2 proteins, Direct activation of BAX/BAK, Disruption of inhibitor of apoptosis proteins (IAP)

Biological Functions

Apoptosis
Cell death
Stress response
Tumor suppression

Disease Associations

Cancer
Neurodegenerative disease
Infection
Other

Safety Considerations

  • On-target toxicity in normal tissues
  • Hematological toxicity (e.g. neutropenia with BCL-2 inhibitors)
  • Resistance via upregulation of anti-apoptotic proteins
  • Off-target activation of apoptosis in non-cancerous cells

Interacting Drugs

BCL-2 inhibitors (venetoclax)
MCL-1 inhibitors
BH3 mimetics
smac mimetics

Associated Biomarkers

Biomarker
Cytochrome c release
Caspase-9 and caspase-3 activation
Expression of BCL-2 family proteins (e.g. BCL-2, MCL-1, BAX, BAK)
SMAC/DIABLO release