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Updated: Feb 20, 2026

Examining BCL-2 Family Function with Large Unilamellar Vesicles
Published on: October 5, 2012
MOMP, cell suicide as a BCL-2 family business
Halime Kalkavan1, Douglas R Green1
1Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
Abstract:
Apoptosis shapes development and differentiation, has a key role in tissue homeostasis, and is deregulated in cancer. In most cases, successful apoptosis is triggered by mitochondrial outer membrane permeabilization (MOMP), which defines the mitochondrial or intrinsic pathway and ultimately leads to caspase activation and protein substrate cleavage. The mitochondrial apoptotic pathway centered on MOMP is controlled by an intricate network of events that determine the balance of the cell fate choice between survival and death. Here we will review how MOMP proceeds and how the main effectors cytochrome c, a heme protein that has a crucial role in respiration, and second mitochondria-derived activator of caspase (SMAC), as well as other intermembrane space proteins, orchestrate caspase activation. Moreover, we discuss recent insights on the interplay of the upstream coordinators and initiators of MOMP, the BCL-2 family. This review highlights how our increasing knowledge on the regulation of critical checkpoints of apoptosis integrates with understanding of cancer development and has begun to translate into therapeutic clinical benefit.
Insights
This review details mitochondrial outer membrane permeabilization (MOMP), the key step in apoptosis. It explains how MOMP, cytochrome c, and SMAC activate caspases, impacting cancer and therapy.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Apoptosis is crucial for development, homeostasis, and preventing cancer.
- Mitochondrial outer membrane permeabilization (MOMP) triggers the intrinsic apoptotic pathway.
- Dysregulation of apoptosis is implicated in cancer development.
Purpose of the Study:
- To review the mechanisms of MOMP and caspase activation.
- To discuss the roles of cytochrome c, SMAC, and BCL-2 family proteins.
- To highlight the therapeutic implications of understanding apoptosis regulation.
Main Methods:
- Literature review of apoptosis research.
- Analysis of molecular mechanisms controlling MOMP.
- Integration of knowledge on apoptosis regulation and cancer therapy.
Main Results:
- MOMP is a central event in apoptosis, leading to caspase activation.
- Cytochrome c and SMAC are key effectors released during MOMP.
- The BCL-2 family proteins act as critical regulators of MOMP.
- Understanding apoptosis checkpoints offers therapeutic potential.
Conclusions:
- The intricate regulation of MOMP dictates cell fate.
- Knowledge of apoptosis pathways is advancing cancer treatment.
- Targeting apoptosis offers promising therapeutic strategies.
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