Identification of Ste4 as a potential regulator of Byr2 in the sexual response pathway of Schizosaccharomyces pombe.
A conserved MAP kinase cascade is central to signal transduction in both simple and complex eukaryotes. In the yeast Schizosaccharomyces pombe, Byr2, a homolog of mammalian MAPK/ERK kinase kinase and Saccharomyces cerevisiae STE11, is required for pheromone-induced sexual differentiation. A screen for S. pombe proteins that interact with Byr2 in a two-hybrid system led to the isolation of Ste4, a protein that is known to be required for sexual function. Ste4 binds to the regulatory region of Byr2. This binding site is separable from the binding site for Ras1. Both Ste4 and Ras1 act upstream of Byr2 and act at least partially independently. Ste4 contains a leucine zipper and is capable of homotypic interaction. Ste4 has regions of homology with STE50, an S. cerevisiae protein required for sexual differentiation that we show can bind to STE11.
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Cold Spring Harbor Laboratory, New York 11724, USA.
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Van Aelst
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D001665:Binding Sites; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D003433:Crosses, Genetic; D017931:DNA Primers; D005656:Fungal Proteins / Q000378:metabolism*; D044387:GTP-Binding Protein beta Subunits; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005838:Genotype; D020962:Heterotrimeric GTP-Binding Proteins; D016350:Leucine Zippers; D020930:MAP Kinase Kinase Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D016297:Mutagenesis, Site-Directed; D010675:Pheromones / Q000502:physiology; D016133:Polymerase Chain Reaction; D011494:Protein Kinases / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011995:Recombination, Genetic; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins; D015398:Signal Transduction; D013172:Spores, Fungal; D014157:Transcription Factors / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism
D017931:DNA Primers; D005656:Fungal Proteins; D044387:GTP-Binding Protein beta Subunits; D010675:Pheromones; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C067576:Ste4 protein, S cerevisiae; D014157:Transcription Factors; C071596:ste11 protein, S pombe; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C077892:BYR2 protein, S pombe; D020930:MAP Kinase Kinase Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins; C489014:RAS1 protein, S cerevisiae; C492657:Ras1 protein, S pombe; D018631:ras Proteins