Ste50p is involved in regulating filamentous growth in the yeast Saccharomyces cerevisiae and associates with Ste11p.
STE50 is required to sustain pheromone-induced signal transduction in S. cerevisiae. Here we report that Ste50p is involved in regulating pseudohyphal development. Both of these processes are also dependent on Ste11p. Deletion of STE50 leads to defects in filamentous growth, which can be suppressed by overproduction of Ste11p. Overexpression of STE11 also suppresses the mating defects of ste50 mutants. We have analysed the physical association between Ste50p and Ste11p in extracts of cells harvested under various conditions. A Ste11p-Ste50p complex can be isolated from extracts of cells in which the pheromone response has been activated, as well as from normally growing cells. Formation of the Ste50p-Ste11p complex does not require G(alpha), G(beta), Ste20p or Ste5p. Oligomerisation of Ste11p is shown to be independent of activation of the pheromone response pathway, and occurs in the absence of Ste50p. We conclude that Ste50p is necessary for Ste11p activity in at least two differentiation programmes: mating and filamentous growth.
Ramezani Rad
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Institut für Mikrobiologie, Heinrich-Heine-Universität Düsseldorf, Germany. ramezani@uni-duesseldorf.de
Jansen
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G
Bühring
F
F
Hollenberg
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CP
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D005656:Fungal Proteins / Q000096:biosynthesis / Q000378:metabolism* / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000502:physiology; D005800:Genes, Fungal; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation; D010675:Pheromones / Q000378:metabolism / Q000502:physiology; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000254:growth & development* / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D015398:Signal Transduction; D014157:Transcription Factors
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010675:Pheromones; C080321:STE5 protein, S cerevisiae; C079506:STE50 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C071596:ste11 protein, S pombe; D017346:Protein Serine-Threonine Kinases; D020930:MAP Kinase Kinase Kinases; C078754:STE20 protein, S cerevisiae; C067018:Ste11 protein, S cerevisiae; D019204:GTP-Binding Proteins