Regulation of apoptosis by BH3 domains in a cell-free system

Abstract

The BH3 domains of pro-apoptotic proteins are sufficient to trigger cytochrome c release, caspase activation and apoptosis. These results support a model in which pro-apoptotic proteins, such as Bax and Bak, bind to Bcl-2 via their BH3 domains, inactivating the normal ability of Bcl-2 to suppress apoptosis. The ability of synthetic peptides to reproduce the effect of pro-apoptotic BH3 domains suggests that such peptides may provide the basis for engineering reagents to control the initiation of apoptosis.

Bcl-2 family proteins as targets for anticancer drug design

“…Using a cell-free system based on extracts of Xenopus eggs as a biochemical model for the apoptotic process, the biological activity of synthetic BH3 peptides in triggering apoptosis was examined (Cosulich et al, 1997). Peptides of 16 amino acids derived from the BH3 domains of Bak, Bax or Bid were found to have apoptosis inducing activity by causing rapid activation of caspases, whereas a Bak BH3 mutant peptide containing Ala substitution at Leu-78, which is critical for Bcl-x L binding (Sattler et al, 1997) and a peptide derived from the BH3 domain of anti-apoptotic Bcl-2 did not show any e ect.…”

Recent advances in the development of anticancer agents targeting cell death inhibitors in the Bcl-2 protein family

“…151 The induction of apoptosis signal transduction by BH3 peptides derived from proapoptotic proteins was first studied in cell-free extracts of Xenopus eggs. 152 In this system, both Bax and Bak BH3 peptides, but not Bcl-2 BH3 peptide, displayed apoptotic activity, as measured by caspase activation. 152 Subsequent studies investigated the ability of BH3 peptides to promote apoptosis in cell-free extracts from mammalian cells.…”

“…152 In this system, both Bax and Bak BH3 peptides, but not Bcl-2 BH3 peptide, displayed apoptotic activity, as measured by caspase activation. 152 Subsequent studies investigated the ability of BH3 peptides to promote apoptosis in cell-free extracts from mammalian cells. The release of cytochrome c from mitochondria, which is critical for caspase activation, has commonly been used as a marker of apoptosis induction in these studies.…”

Stress in the brain: novel cellular mechanisms of injury linked to Alzheimer's disease

“…The mitochondrial pathway is associated with the release of cytochrome c and subsequent activation of caspase 9 followed by activation of caspase 3 [127]. The process is regulated by the Bcl-2 subfamily BH3-only proteins, which are normally located in cellular compartments other than mitochondria, but translocate to the mitochondria in response to apoptotic stimuli [54]. The translocation of these proteins delivers an apoptotic signal to mitochondria through the interaction with Bax to induce the release of cytochrome c that then binds to apoptotic protease activating factor-1 (Apaf-1).…”