Oligomerization of the Mitochondrial Protein VDAC1

The voltage-dependent anion channel (VDAC1), lying in the mitochondrial outer membrane (OMM), mediates the transport of ions and metabolites, thus controlling the cross talk between mitochondria and the rest of the cell. VDAC1 has also been recognized as a key protein in mitochondria-mediated apoptosis, is the proposed target for the pro- and antiapoptotic Bcl-2-family of proteins and is involved in apoptotic protein release from the mitochondria. Questions, however, remain as to if and how VDAC1 mediates the transfer of apoptotic proteins across the OMM. Our recent studies suggest that upon apoptosis induction, VDAC1 oligomerizes to form a new large pore allowing the passage of a folded protein, like cytochrome c. This review provides insight into the central role of VDAC1 in mammalian cell life and death and emphasizes VDAC1 function in apoptosis, focusing on VDAC1 oligomerization as a key step in mitochondria-mediated apoptosis and key structural features of VDAC1 that mediate its apoptotic function.