Unpublished draft

BAK1 (BAK)

BAK (BCL-2 homologous antagonist/killer) is a mitochondrial outer-membrane protein that forms the apoptotic pore together with BAX.

Function

BAK is anchored permanently in the mitochondrial outer membrane in an inactive conformation. Stress-activated BH3-only proteins — BID and BIM in particular — expose the helix that lets BAK oligomerize; the BAK–BAX oligomers permeabilize the outer membrane, releasing cytochrome c into the cytosol and committing the cell to caspase-dependent death. Anti-apoptotic family members (BCL-2, BCL-xL, MCL-1) hold BAK shut, and the MCL-1–BAK pair is a common resistance axis in cancer therapy.

In cancer

Cells lacking both BAX and BAK resist mitochondrial apoptosis almost completely, so the pair controls