| Background |
Puma (p53 upregulated modulator of apoptosis) is a "BH3-only" Bcl-2 family member originally identified in differential gene expression studies as a p53-inducible gene The "BH3-only" family members include Bad, Bid, Bik, Hrk, Bim, and Noxa, all of which contain a BH3 domain but lack other conserved domains, BH1 and BH2, and generally promote apoptosis by binding to and antagonizing anti-apoptotic Bcl-2 family members through BH3 domain interactions Two BH3-containing proteins are produced from the puma gene, Puma-α and Puma-β, both of which are induced by p53, bind Bcl-2 and Bcl-xL, localize to the mitochondria, and promote cytochrome c release and apoptosis Puma plays a critical role in the p53 tumor suppressor pathway. Targeted disruption of the puma gene impairs p53-mediated apoptosis and tumor suppression Puma knockout mice show defects from multiple apoptotic stimuli, including ionizing irradiation, deregulated c-Myc expression, and cytokine withdrawal.
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