Voltage dependent anion selective channel protein 1 (VDAC/Porin) belongs to the eukaryotic mitochondrial porin family and forms a channel through the mitochondrial outer membrane and also the plasma membrane. The channel allows diffusion of small hydrophilic molecules; it adopts an open conformation at low or zero membrane potential and a closed conformation at potentials above 30-40 mV. The open state has a weak anion selectivity whereas the closed state is cation selective. VDAC/Porin expression is observed in the heart,liver and skeletal muscle.