SERINE-THREONINE PROTEIN-KINASE ACTIVITY OF ELM1P, A REGULATOR OF MORPHOLOGIC DIFFERENTIATION IN SACCHAROMYCES-CEREVISIAE

The Saccharomyces cerevisiae gene ELM1 regulates morphologic different iation and its nucleotide sequence predicts a novel protein kinase. El m1p was expressed in yeast and insect cells and purified. Elm1p displa yed protein kinase activity in autophosphorylation assays and towards exogenous substrates. Serine and threonine residues were identified as the accepters in these reactions. These data together with previous g enetic analysis of ELM1 function indicate that phosphorylation on seri ne and/or threonine residues of a particular substrate or set of subst rates by Elm1p is required for repression of the filamentous growth di fferentiation state. (C) 1997 Federation of European Biochemical Socie ties.