The hexokinase 2 protein participates in regulatory DNA-protein complexes necessary for glucose repression of the SUC2 gene in Saccharomyces cerevisiae

FEBS Lett. 1998 Aug 28;434(1-2):71-6. doi: 10.1016/s0014-5793(98)00872-2.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • DNA, Fungal / genetics
  • DNA, Fungal / metabolism*
  • Gene Expression Regulation, Fungal / drug effects*
  • Glucose / pharmacology*
  • Glycoside Hydrolases / genetics*
  • Glycoside Hydrolases / metabolism
  • Hexokinase / metabolism*
  • Molecular Sequence Data
  • Mutation
  • Protein Binding
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism*
  • beta-Fructofuranosidase

Substances

  • DNA, Fungal
  • Hexokinase
  • Glycoside Hydrolases
  • beta-Fructofuranosidase
  • Glucose