The p53 upregulated modulator of apoptosis, or PUMA, is a pro-apoptotic member of the Bcl-2 protein family.1, 2 The PUMA gene is located at 19q.3 PUMA transcript is contained within 4 exons, with the presumptive initiation codon in exon 2. The predicted 193-amino acid PUMA protein shares 91 % amino acid identity with the murine sequence. Bcl-2 family members can form hetero-or homodimers, and they act as anti-or pro-apoptotic regulators that are involved in a wide variety of cellular activities. The expression of PUMA is regulated by the tumor suppressor p53, and PUMA has been shown to be involved in p53-mediated apoptosis. Additionally, PUMA encodes 2 BH3 domain-containing proteins, PUMA-alpha and PUMA-beta, that are produced through the use of an alternative first exon and are induced in cells following p53 activation.4 Furthermore, PUMA couples the nuclear and cytoplasmic proapoptotic functions of p53.5Synonyms: BBC3, Bcl-2-binding component 3, JFY-1, p53 up-regulated modulator of apoptosis