Fig. 1

Mitochondrial p53 activates the intrinsic apoptotic pathway. p53 binds and induces the release of Bak (BCL-2 antagonist killer 1) and Bax (BCL-2 associated X protein) from the anti-apoptotic factors [Bcl-2 (B-cell lymphoma 2), Mcl-1 (Induced myeloid leukemia cell differentiation protein), and Bcl-XL (BCL-2 related protein, long isoform)]. The effectors Bak and Bax homo-oligomerize and lead to the formation of permeable pores on the mitochondrial outer membrane. The mitochondrial membrane potential is disrupted, and cytochrome c is released, which leads to the formation of the apoptosome, caspase activation, and ultimately apoptotic cell death