Document Detail


Identification and metabolic role of the mitochondrial aspartate-glutamate transporter in Saccharomyces cerevisiae.
MedLine Citation:
PMID:  14622413     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The malate-aspartate NADH shuttle in mammalian cells requires the activity of the mitochondrial aspartate-glutamate carrier (AGC). Recently, we identified in man two AGC isoforms, aralar1 and citrin, which are regulated by calcium on the external face of the inner mitochondrial membrane. We have now identified Agc1p as the yeast counterpart of the human AGC. The corresponding gene was overexpressed in bacteria and yeast mitochondria, and the protein was reconstituted in liposomes where it was identified as an aspartate-glutamate transporter from its transport properties. Furthermore, yeast cells lacking Agc1p were unable to grow on acetate and oleic acid, and had reduced levels of valine, ornithine and citrulline; in contrast they grew on ethanol. Expression of the human AGC isoforms can replace the function of Agc1p. However, unlike its human orthologues, yeast Agc1p catalyses both aspartate-glutamate exchange and substrate uniport activities. We conclude that Agc1p performs two metabolic roles in Saccharomyces cerevisiae. On the one hand, it functions as a uniporter to supply the mitochondria with glutamate for nitrogen metabolism and ornithine synthesis. On the other, the Agc1p, as an aspartate-glutamate exchanger, plays a role within the malate-aspartate NADH shuttle which is critical for the growth of yeast on acetate and fatty acids as carbon sources. These results provide strong evidence of the existence of a malate-aspartate NADH shuttle in yeast.
Authors:
S Cavero; A Vozza; A del Arco; L Palmieri; A Villa; E Blanco; M J Runswick; J E Walker; S Cerdán; F Palmieri; J Satrústegui
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Molecular microbiology     Volume:  50     ISSN:  0950-382X     ISO Abbreviation:  Mol. Microbiol.     Publication Date:  2003 Nov 
Date Detail:
Created Date:  2003-11-19     Completed Date:  2004-04-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8712028     Medline TA:  Mol Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1257-69     Citation Subset:  IM    
Affiliation:
Departmento Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-C S I C, Madrid, Spain.
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MeSH Terms
Descriptor/Qualifier:
Acetates / metabolism
Amino Acid Transport Systems, Acidic / genetics,  metabolism*
Animals
Antiporters / genetics,  metabolism*
Aspartic Acid / metabolism
Carbon Dioxide / metabolism
Glutamic Acid / metabolism
Humans
Liposomes / chemistry,  metabolism
Malates / metabolism
Membrane Potentials
Mitochondria / metabolism*
Ornithine / metabolism
Protein Isoforms / genetics,  metabolism
Recombinant Proteins / genetics,  metabolism
Saccharomyces cerevisiae / metabolism*
Saccharomyces cerevisiae Proteins / genetics,  metabolism*
Chemical
Reg. No./Substance:
0/Acetates; 0/Amino Acid Transport Systems, Acidic; 0/Antiporters; 0/Liposomes; 0/Malates; 0/Protein Isoforms; 0/Recombinant Proteins; 0/Saccharomyces cerevisiae Proteins; 0/aspartate-glutamate carrier; 124-38-9/Carbon Dioxide; 56-84-8/Aspartic Acid; 56-86-0/Glutamic Acid; 6915-15-7/malic acid; 7006-33-9/Ornithine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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