Of the variety of nucleotides tested on VDAC channels reconstituted into
planar membranes (including cyclic nucleotides and ATP, only NADH and
the Mg-NADPH complex (not their oxidized forms) influenced the probability
of VDAC closure (Zizi et al., 1994; Lee et al., 1996). While the direct
effects on the VDAC channels are subtle, as one might expect from delicate
control mechanism, effects on isolated mitochondria are quite pronounced.
On VDAC channels there is an increase in voltage dependence of the channels.
In isolated mitochondria with intact outer membranes, the permeability
of the outer membranes to ADP was reduced by a factor of 6. One can only
conclude that the mitochondrial environment in which the VDAC channels
are located, and possible interaction with other proteins caused a larger
response to NADH.
Zizi, M., Forte, M., Blachly-Dyson, E. and Colombini, M. 1994. NADH regulates the gating of VDAC, the mitochondrial outer membrane channel. Journal of Biological Chemistry, 269:1614-1616.
Lee, A., Zizi, M. and Colombini, M. 1994. b-NADH decreases the permeability of the mitochondrial outer membrane to ADP by a factor of 6. Journal of Biological Chemistry, 269: 30974-30980.
Lee, A., Xu, X., and Colombini, M. 1996. The role of pyridine dinucleotides in regulating the permeability of the mitochondrial outer membrane. Journal of Biological Chemistry, 271: 26724-26731.
Lee, A., Xu, X., Blachly-Dyson, E., Forte, M. and Colombini, M. 1997. The role of yeast VDAC genes on the permeability of the mitochondrial outer membrane. Journal of Membrane Biology, 161:173-181.