BH3-Dependent and Independent Activation of BAX and BAK in Mitochondrial Apoptosis

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Mitochondria are central to mammalian apoptosis, a programmed cell death process.
• Mitochondrial outer membrane permeabilization (MOMP) is a key step, activating caspases and causing mitochondrial dysfunction.
• The BCL-2 protein family critically regulates MOMP.

Purpose of the Study:

• To elucidate the regulatory network of BCL-2 family proteins in controlling cell survival and death.
• To highlight the role of BCL-2 proteins in integrating cellular signals for apoptosis.
• To underscore the therapeutic potential of targeting protein-protein interactions in cancer.

Main Methods:

• Analysis of the BCL-2 protein family interactions.
• Investigating the hierarchical network of pro- and anti-apoptotic proteins.
• Review of research on BCL-2-regulated apoptosis over 30 years.

Main Results:

• BAX and BAK are effectors of MOMP, while BCL-2, BCL-X_L, and MCL-1 are inhibitors.
• BH3-only proteins modulate apoptosis by interacting with BAX, BAK, and their inhibitors.
• The BCL-2 family forms a network that dictates cell fate based on environmental and developmental cues.

Conclusions:

• The BCL-2 protein network precisely controls mitochondrial integrity and cell death decisions.
• Understanding this pathway is vital for comprehending physiological and pathological processes.
• Targeting BCL-2 interactions has yielded the first anti-cancer drug for protein-protein interactions.