Multiple conductance channel activity of wild-type and voltage-dependent anion-selective channel (VDAC)-less yeast mitochondria.
Yeast mitoplasts (mitochondria with the outer membrane stripped away) exhibit multiple conductance channel activity (MCC) in patch-clamp experiments that is very similar to the activity previously described in mammalian mitoplasts. The possible involvement of the voltage-dependent anion-selective channel (VDAC) of the outer membrane in MCC activity was explored by comparing the channel activity in wild-type yeast mitoplasts with that of a VDAC-deletion mutant. The channel activity recorded from the mutant is essentially the same as that of the wild-type in the voltage range of -40 to 30 mV. These observations indicate that VDAC is not required for MCC activity. Interestingly, the channel activity of the VDAC-less yeast mitoplasts exhibits altered gating properties at transmembrane potentials above and below this range. We conclude that the deletion of VDAC somehow results in a modification of MCC's voltage dependence. In fact, the voltage profile recorded from the VDAC-less mutant resembles that of VDAC.
Lohret
T A
TA
Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509, USA.
Kinnally
K W
KW
D000818:Animals; D015153:Blotting, Western; D004553:Electric Conductivity; D004591:Electrophoresis, Polyacrylamide Gel; D007425:Intracellular Membranes / Q000502:physiology; D007473:Ion Channels / Q000502:physiology*; D007700:Kinetics; D008322:Mammals; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000302:isolation & purification / Q000502:physiology*; D008928:Mitochondria / Q000502:physiology*; D018272:Porins; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D050994:Voltage-Dependent Anion Channels
D007473:Ion Channels; D008565:Membrane Proteins; D018272:Porins; D050994:Voltage-Dependent Anion Channels