BAX, also named as BCL2L4, is a pro-apoptotic member of the Bcl-2 protein family, which plays a pivotal role in controlling cell life and death. Bax largely localizes to the cytoplasm of healthy cells, but accumulates on the outer mitochondrial membrane upon apoptosis induction (PMID: 9108035). BAX can commit a cell to apoptosis by translocation from the cytosol to the mitochondria and permeabilization of the outer mitochondrial membrane, which leads to the release of cytochrome c from mitochondria (PMID: 21763611). The expression of BAX is upregulated by the tumor suppressor protein p53, and BAX has been shown to be involved in p53-mediated apoptosis (PMID: 8183579).