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Functional domains of yeast hexokinase 2

Hkx2 (hexokinase 2) from Saccharomyces cerevisiae was one of the first metabolic enzymes described as a multifunctional protein. Hxk2 has a double subcellular localization: it functions as a glycolytic enzyme in the cytoplasm and as a regulator of gene transcription of several Mig1-regulated genes i...

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Autores principales: Peláez, Rafael, Herrero, Pilar, Moreno, Fernando
Formato: Texto
Lenguaje:English
Publicado: Portland Press Ltd. 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995421/
https://www.ncbi.nlm.nih.gov/pubmed/20815814
http://dx.doi.org/10.1042/BJ20100663
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author Peláez, Rafael
Herrero, Pilar
Moreno, Fernando
author_facet Peláez, Rafael
Herrero, Pilar
Moreno, Fernando
author_sort Peláez, Rafael
collection PubMed
description Hkx2 (hexokinase 2) from Saccharomyces cerevisiae was one of the first metabolic enzymes described as a multifunctional protein. Hxk2 has a double subcellular localization: it functions as a glycolytic enzyme in the cytoplasm and as a regulator of gene transcription of several Mig1-regulated genes in the nucleus. To get more insights into the structure–function relationships of the Hxk2 protein, we followed two different approaches. In the first, we deleted the last eight amino acids of Hxk2 and replaced Ser(304) with phenylalanine to generate Hxk2(wca). Analysis of this mutant demonstrated that these domains play an essential role in the catalytic activity of yeast Hxk2, but has no effect on the regulatory function of this protein. In the second, we analysed whether amino acids from Lys(6) to Met(15) of Hxk2 (Hxk2(wrf)) are essential for the regulatory role of Hxk2 and whether there is an effect on the hexose kinase activity of this protein. In the present paper, we report that the Hxk2(wca) mutant protein interacts with the Mig1 transcriptional repressor and the Snf1 protein kinase in the nucleus at the level of the SUC2–Mig1 repressor complex. We have demonstrated that Hxk2(wca) maintained full regulatory function because the glucose-repression signalling of the wild-type machinery is maintained. We also report that the Hxk2(wrf) mutant allele is incapable of glucose repression signalling because it does not interact with Mig1 at the level of the SUC2–Mig1 repressor complex. The two mutants, Hxk2(wca) and Hxk2(wrf) retain single functions, as a transcriptional factor or as an enzyme with hexose-phosphorylating activity, but have lost the original bifunctionality of Hxk2.
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spelling pubmed-29954212010-12-08 Functional domains of yeast hexokinase 2 Peláez, Rafael Herrero, Pilar Moreno, Fernando Biochem J Research Article Hkx2 (hexokinase 2) from Saccharomyces cerevisiae was one of the first metabolic enzymes described as a multifunctional protein. Hxk2 has a double subcellular localization: it functions as a glycolytic enzyme in the cytoplasm and as a regulator of gene transcription of several Mig1-regulated genes in the nucleus. To get more insights into the structure–function relationships of the Hxk2 protein, we followed two different approaches. In the first, we deleted the last eight amino acids of Hxk2 and replaced Ser(304) with phenylalanine to generate Hxk2(wca). Analysis of this mutant demonstrated that these domains play an essential role in the catalytic activity of yeast Hxk2, but has no effect on the regulatory function of this protein. In the second, we analysed whether amino acids from Lys(6) to Met(15) of Hxk2 (Hxk2(wrf)) are essential for the regulatory role of Hxk2 and whether there is an effect on the hexose kinase activity of this protein. In the present paper, we report that the Hxk2(wca) mutant protein interacts with the Mig1 transcriptional repressor and the Snf1 protein kinase in the nucleus at the level of the SUC2–Mig1 repressor complex. We have demonstrated that Hxk2(wca) maintained full regulatory function because the glucose-repression signalling of the wild-type machinery is maintained. We also report that the Hxk2(wrf) mutant allele is incapable of glucose repression signalling because it does not interact with Mig1 at the level of the SUC2–Mig1 repressor complex. The two mutants, Hxk2(wca) and Hxk2(wrf) retain single functions, as a transcriptional factor or as an enzyme with hexose-phosphorylating activity, but have lost the original bifunctionality of Hxk2. Portland Press Ltd. 2010-10-25 2010-11-15 /pmc/articles/PMC2995421/ /pubmed/20815814 http://dx.doi.org/10.1042/BJ20100663 Text en © yyyy The Author(s) The author(s) has paid for this article to be freely available under the terms of the Creative Commons Attribution Non-Commercial Licence (http://creativecommons.org/licenses/by-nc/2.5/) which permits unrestricted non-commercial use, distribution and reproduction in any medium, provided the original work is properly cited. http://creativecommons.org/licenses/by-nc/2.5/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Peláez, Rafael
Herrero, Pilar
Moreno, Fernando
Functional domains of yeast hexokinase 2
title Functional domains of yeast hexokinase 2
title_full Functional domains of yeast hexokinase 2
title_fullStr Functional domains of yeast hexokinase 2
title_full_unstemmed Functional domains of yeast hexokinase 2
title_short Functional domains of yeast hexokinase 2
title_sort functional domains of yeast hexokinase 2
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995421/
https://www.ncbi.nlm.nih.gov/pubmed/20815814
http://dx.doi.org/10.1042/BJ20100663
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