p53 upregulated modulator of apoptosis (PUMA) (PUMA)

The p53 upregulated modulator of apoptosis (PUMA), also known as BCL2 binding component 3 (BBC3), is a potent pro-apoptotic member of the BCL-2 protein family belonging to the BH3-only subgroup (UniProt Q9BXH1). It serves as a critical link between the p53 tumor suppressor pathway and the mitochondrial apoptotic machinery, being transcriptionally induced by p53 in response to DNA damage and other cellular stresses (Nakano & Vousden, 2001). Once expressed, PUMA localizes to the outer mitochondrial membrane where it binds and antagonizes all known anti-apoptotic BCL-2 family members, such as BCL-2, BCL-XL, and MCL-1 (Youle & Strasser, 2008). This interaction releases or directly activates the pore-forming proteins BAX and BAK, leading to mitochondrial outer membrane permeabilization (MOMP), cytochrome c release, and subsequent caspase activation (Certo et al., 2006). In many cancers, the PUMA pathway is disrupted through TP53 mutations or epigenetic silencing, contributing to chemoresistance and tumor survival. Consequently, the BH3 mimetic class of drugs, such as Venetoclax, has been developed to pharmacologically replicate the action of PUMA by binding to anti-apoptotic proteins, thereby restoring the apoptotic threshold in malignant cells (Roberts et al., 2016).

Other names

BCL2 binding component 3BBC3JFY-1PUMA pathwayBCL2 family apoptotic machinery

BH3 mimetics bind to the hydrophobic groove of anti-apoptotic BCL-2 family proteins (e.g., BCL-2, BCL-XL, MCL-1), preventing them from sequestering pro-apoptotic proteins like BAX and BAK, thereby inducing mitochondrial apoptosis.