Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.21/7678
Título: OPI1P translocation to the nucleus is regulated through oxidation by hydrogen peroxide in saccharomyces cerevisiae
Autor: Camelo, C.
Vilas-Boas, F.
Cepeda, A.
Real, C.
Pinto, F.
Costa, G. da
Soares, Helena
Marinho, H. Susana
Cyrne, L.
Palavras-chave: Opi1p
Saccharomyces cerevisiae
Yeast cells
Data: Jun-2016
Citação: Camelo C, Vilas-Boas F, Cepeda A, Real C, Pinto F, Soares H, et al. OPI1P translocation to the nucleus is regulated through oxidation by hydrogen peroxide in saccharomyces cerevisiae. In: CQB Day, Faculdade de Ciências (Lisboa), 28 June 2016.
Resumo: Adaptation of yeast cells to hydrogen peroxide (H2O2) leads to a rapid change in membrane permeability accompanied by a decrease of membrane fluidity and the alteration of its lipid composition, allowing cells to survive to higher doses of H2O2. During adaptation to H2O2 several genes that contain the regulatory element UASINO, and which codify for enzymes involved in phospholipid and fatty acid metabolism, are repressed. This repression is due to the translocation into the nucleus of the endoplasmic reticulum-bound transcriptional repressor Opi1p. However, the mechanisms of regulation of this translocation regulated by H2O2 are still unknown. Oxidation of particular cysteine residues in proteins by H2O2 is involved in signaling cascades that culminate in the regulation of transcription. Opi1p has in its structure four cysteine residues that may be targets of oxidation. Such oxidation might be responsible for the H2O2-dependent translocation of Opi1p to the nucleus and subsequent transcriptional repression of target genes. Opi1p oxidation when cells were exposed to adaptive doses of H2O2 was confirmed by a protein electrophoresis (SDS-PAGE), after tagging oxidized protein cysteine sulphydryl groups with methoxy-polyethylene glycolmaleimide (MAL-PEG). To determine whether Opi1p cysteine residues are responsible for H2O2-mediated translocation of Opi1p to the nucleus, yeast strains with individual mutations in cysteine residues were prepared (cysteine to alanine substitutions). These mutations did not compromise the function of Opi1p as a transcriptional repressor since all cells presented similar levels of expression of a reporter gene containing UASINO. As expected, the wild-type strain displayed Opi1p mainly in the endoplasmic reticulum, which translocated to the nucleus in the presence of H2O2. In clear contrast, Opi1p translocation to the nucleus in cells treated with H2O2 was impaired in the C159A mutant, with Opi1p being equally distributed in the periphery and inside the nucleus. These results identify cysteine residue 159 of Opi1p as responsible for H2O2-mediated translocation of this protein to the nucleus.
Peer review: yes
URI: http://hdl.handle.net/10400.21/7678
Versão do Editor: http://cqb.fc.ul.pt/wp-content/uploads/2016/06/CQB-day-book-of-abstracts2016.pdf
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