An involvement of yeast peroxisomal channels in transmembrane transfer of glyoxylate cycle intermediates.
Int J Biochem Cell Biol
; 41(12): 2546-54, 2009 Dec.
Article
em En
| MEDLINE
| ID: mdl-19712748
ABSTRACT
The separate localization of glyoxylate cycle enzymes in the peroxisomes and the cytosol of the yeast Saccharomyces cerevisiae indicates that the peroxisomal membrane must permit the flow of metabolites between the two compartments. The transfer of these metabolites may require peroxisomal membrane channel(s). We used an electrophysiological approach (reconstitution assay in lipid bilayers) to assess the ability of peroxisomal membrane channels to conduct different solutes including metabolites of the glyoxylate cycle. At least two distinct channel-forming activities were detected in peroxisomal preparations. One of these activities was highly inducible by dithiothreitol and showed large-amplitude current increments when 1M KCl was used as a bath solution. Single-channel analysis revealed that the inducible channel is anion-selective (P(Cl(-)) / P(K(+)) = 2.6; P(citrate)/P(K(+)) = 1.6) and displays flickering at holding potentials over + or - 30mV directed upward or downward relative to the main open state of the channel. The channel inducible by DTT facilitates the transfer of solutes with a molecular mass up to 400Da, sufficient to allow the transmembrane trafficking of glyoxylate cycle intermediates between the peroxisomal lumen and the cytoplasm.
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Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
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Peroxissomos
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Glioxilatos
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Canais Iônicos
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article