Bax/Bak

B-cell lymphoma 2 (Bcl-2) protein is an oncogene that normally acts as an apoptotic inhibitor and localizes to the mitochondrial membrane where it prevents the release of cytochrome c. The Bcl-2 protein family consists of over 20 proteins each containing at least one Bcl-2 homology (BH) domains and have either proapoptic or antiapoptotic activities.

Bcl-2 nineteen-kilodalton interacting protein 3 (BNIP3) is a pro-apoptotic BH3-only protein. BNIP3 localizes to the mitochondrial membrane where it plays a key role in mitochondrial autophagy and cell death pathways. Similar to other Bcl-2 family members, BNIP3 binds to Bcl-2 and can activate the downstream effectors of Bax/Bak.