Lap4, a vacuolar aminopeptidase I, is involved in cadmium-glutathione metabolism

In Saccharomyces cerevisiae, accumulation of cadmium-glutathione complex in cytoplasm inhibits cadmium absorption, glutathione transferase 2 is required for the formation of the complex and the vacuolar gamma-glutamyl transferase participates of the first step of glutathione degradation. Here, we pr...

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Bibliographic Details
Published in:Biometals 2009-04, Vol.22 (2), p.243-249
Main Authors: Adamis, Paula D. B, Mannarino, Sergio C, Riger, Cristiano J, Duarte, Giselle, Cruz, Ana, Pereira, Marcos D, Eleutherio, Elis C. A
Format: Article
Language:English
Subjects:
Aminopeptidases - chemistry
Aminopeptidases - genetics
Aminopeptidases - physiology
Biochemistry
Biomedical and Life Sciences
Cadmium
Cadmium - metabolism
Cadmium - toxicity
Cell Biology
Cytoplasm - metabolism
Enzymes
gamma-Glutamyltransferase - metabolism
Gene Expression Regulation, Fungal
Glutathione - metabolism
Life Sciences
Lipid Peroxidation
Medicine/Public Health
Metabolism
Microbiology
Models, Biological
Mutagenesis
Mutation
Oxidative Stress
Oxygen - chemistry
Peptides
Pharmacology/Toxicology
Plant Physiology
Saccharomyces cerevisiae
Saccharomyces cerevisiae - enzymology
Saccharomyces cerevisiae Proteins - genetics
Saccharomyces cerevisiae Proteins - physiology
Vacuoles - enzymology
Yeast
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Summary:In Saccharomyces cerevisiae, accumulation of cadmium-glutathione complex in cytoplasm inhibits cadmium absorption, glutathione transferase 2 is required for the formation of the complex and the vacuolar gamma-glutamyl transferase participates of the first step of glutathione degradation. Here, we proposed that Lap4, a vacuolar amino peptidase, is involved in glutathione catabolism under cadmium stress. Saccharomyces cerevisiae cells deficient in Lap4 absorbed almost 3-fold as much cadmium as the wild-type strain (wt), probably due to the lower rate of cadmium-glutathione complex synthesis in the cytoplasm. In wt, but not in lap4 strain, the oxidized/reduced GSH ratio and the Gtt activity increased in response to cadmium, confirming that the mutant is deficient in the synthesis of the complex probably because the degradation of vacuolar glutathione is impaired. Thus, under cadmium stress, Lap4 and gamma-glutamyl transferase seem to work together to assure an efficient glutathione turnover stored in the vacuole.
ISSN:0966-0844
1572-8773
DOI:10.1007/s10534-008-9160-9