Bcl-2 family protein complex

Definition

Target type: cellularcomponent

A protein complex that consists of members of the Bcl-2 family of anti- and proapoptotic regulators. Bcl-2 proteins respond to cues from various forms of intracellular stress, such as DNA damage or cytokine deprivation, and interact with opposing family members to determine whether or not the caspase proteolytic cascade should be unleashed. [GOC:so, PMID:14634621]

The Bcl-2 family protein complex is a multi-protein assembly that plays a central role in regulating apoptosis, or programmed cell death. This complex forms within the mitochondrial outer membrane, a critical location for its function. The complex is composed of both pro-apoptotic (death-promoting) and anti-apoptotic (death-inhibiting) members of the Bcl-2 family. These proteins contain a conserved Bcl-2 homology domain (BH) that allows them to interact with each other and with other mitochondrial proteins. The pro-apoptotic proteins, such as Bax and Bak, are typically inactive in healthy cells. However, in response to apoptotic stimuli, they undergo conformational changes that expose their BH3 domain. This allows them to bind to anti-apoptotic proteins like Bcl-2 and Bcl-xL, which are normally found in the mitochondrial outer membrane. The binding of pro-apoptotic proteins to anti-apoptotic proteins disrupts the inhibitory activity of the anti-apoptotic proteins, leading to the formation of pores in the mitochondrial outer membrane. These pores allow the release of cytochrome c and other pro-apoptotic factors from the mitochondrial intermembrane space into the cytoplasm. This triggers a cascade of events that ultimately leads to the activation of caspases, a family of proteases responsible for the execution of apoptosis. The cellular component of the Bcl-2 family protein complex is therefore the mitochondrial outer membrane, where these proteins interact to control the delicate balance between life and death within a cell.'
"

Proteins (6)

Compounds (86)