A working model of VDAC regulation of ATP flux. A rectangular section of membrane containing 4 channels is illustrated both in oblique view (lower) and top view (upper). The design of the channels embodies our current understanding of the structure of VDAC and of its gating process. The membrane potential drives a portion of the wall of the channel, that serves as a positively-charged voltage sensor (colored blue), out of the channel during the closing process resulting in a net negatively charged region (pink) within the pore. The swarm of ATP molecules are illustrated as red ellipsoids. The relative sizes of the pores and ATP are about to scale.