title: The hexokinase 2 protein participates in regulatory DNA-protein complexes necessary for glucose repression of the SUC2 gene in Saccharomyces cerevisiae.
abstract: The HXK2 gene plays an important role in glucose repression in the yeast Saccharomyces cerevisiae. Recently we have described that the HXK2 gene product, isoenzyme 2 of hexokinase, is located both in the nucleus and in the cytoplasm of S. cerevisiae cells. In this work we used deletion analysis to identify the essential part of the protein-mediating nuclear localisation. Determinations of fructose-kinase activity and immunoblot analysis using anti-Hxk2 antibodies in isolated nuclei, together with observations of the fluorescence distribution of Hxk2-GFP fusion protein in cells transformed with an HXK2::gfp mutant gene, indicated that the decapeptide KKPQARKGSM, located between amino acid residues 7 and 16 of hexokinase 2, is important for nuclear localisation of the protein. Further experimental evidence, measuring invertase activity in wild-type and mutant cells expressing a truncated version of the Hxk2 protein unable to enter the nucleus, shows that a nuclear localisation of Hxk2 is necessary for glucose repression signalling of the SUC2 gene. Furthermore, we demonstrate using gel mobility shift analysis that Hxk2 participates in DNA-protein complexes with cis-acting regulatory elements of the SUC2 gene promoter.
authors.affiliation: Departamento de Bioquímica y Biologia Molecular, Instituto Universitario de Biotecnología de Asturias, Universidad de Oviedo, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Herrero
authors.forename: C
authors.initials: C
authors.lastname: Martínez-Campa
authors.forename: F
authors.initials: F
authors.lastname: Moreno
mesh_terms: D000595:Amino Acid Sequence; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D005947:Glucose / Q000494:pharmacology*; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000378:metabolism; D006593:Hexokinase / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D043324:beta-Fructofuranosidase
chemical_list: D004271:DNA, Fungal; D006593:Hexokinase; D006026:Glycoside Hydrolases; D043324:beta-Fructofuranosidase; D005947:Glucose