Under conditions of insufficient permeability of VDAC1, external NADH may use the TOM complex channel to cross the outer membrane of Saccharomyces cerevisiae mitochondria

Thus far, only three channel-forming activities have been identified in the outer membrane of the yeast Saccharomyces cerevisiae mitochondria. Two of them, namely the TOM complex channel (translocase of the outer membrane) and the PSC (peptide-sensitive channel) participate in protein translocation...

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Bibliographic Details
Published in:Journal of bioenergetics and biomembranes 2001-04, Vol.33 (2), p.119-126
Main Authors: Antos, N, Stobienia, O, Budzińska, M, Kmita, H
Format: Article
Language:English
Subjects:
Intracellular Membranes - metabolism
Membrane Transport Proteins - metabolism
Membranes
Metabolites
Mitochondria
Mitochondria - metabolism
NAD - metabolism
Oxidation-Reduction
Permeability
Porins - metabolism
Recombinant Fusion Proteins - metabolism
Saccharomyces cerevisiae - metabolism
Saccharomyces cerevisiae Proteins - metabolism
Tetrahydrofolate Dehydrogenase - metabolism
Translocation
Voltage-Dependent Anion Channel 1
Voltage-Dependent Anion Channel 2
Voltage-Dependent Anion Channels
Yeasts
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Summary:Thus far, only three channel-forming activities have been identified in the outer membrane of the yeast Saccharomyces cerevisiae mitochondria. Two of them, namely the TOM complex channel (translocase of the outer membrane) and the PSC (peptide-sensitive channel) participate in protein translocation and are probably identical, whereas a channel-forming protein called VDAC (voltage-dependent anion channel) serves as the major pathway for metabolites. The VDAC is present in two isoforms (VDAC1 and VDAC2) of which only VDAC1 has been shown to display channel-forming activity. Moreover, the permeability of VDAC1 has been reported to be limited in uncoupled mitochondria of S. cerevisiae. The presented data indicate that in S. cerevisiae-uncoupled mitochondria, external NADH, applied at higher concentrations (above 50 nmoles per 0.1 mg of mitochondrial protein), may use the TOM complex channel, besides VDAC1, to cross the outer membrane. Thus, the permeability of VDAC1 could be a limiting step in transport of external NADH across the outer membrane and might be supplemented by the TOM complex channel.
ISSN:0145-479X
1573-6881
DOI:10.1023/A:1010748431000