Saccharomyces cerevisiae gene YMR291W/TDA1 mediates the in vivo phosphorylation of hexokinase isoenzyme 2 at serine-15

Hxk2 is the predominant hexokinase of Saccharomyces cerevisiae during growth on glucose. In addition to its role in glycolysis, the enzyme is involved in glucose sensing and regulation of gene expression. Glucose limitation causes the phosphorylation of Hxk2 at serine-15 which affects the nucleo-cytoplasmic distribution and dimer stability of the enzyme. In order to identify the responsible kinase, we screened selected protein kinase single-gene deletion mutants by high resolution clear native PAGE. Deletion of YMR291W/TDA1 resulted in the absence of the Hxk2 phosphomonomer, indicating an indispensable role of the corresponding protein in Hxk2 phosphorylation.

► The monomer–homodimer equilibrium of Hxk2 is affected by serine-15 phosphorylation.
► High resolution clear native PAGE is appropriate for phosphohexokinase detection.
► Protein kinase “single-gene” deletion mutants were screened for Hxk2 phosphorylation.
► Ymr291W/Tda1 is indispensably required for serine-15 phosphorylation of Hxk2.