Saccharomyces cerevisiae STE11 may contribute to the stabilities of a scaffold protein, STE5, in the pheromone signaling pathway.
Saccharomyces cerevisiae STE5 is an essential component of the pheromone-mediated-mitogen activated protein kinase (MAPK) pathway. The STE5 protein recruits MAPK module kinases (STE11, STE7, and FUS3) to give a specificity for the pheromone pathway. The STE5 protein contains a putative PEST motif for ubiquitin-dependent protein degradation, and its level may be important for regulation of pheromone signal transduction. In this article, we studied the roles of proteins associated with the STE5 protein for its stabilization by analyzing ste deletion mutants. Here, we found that the STE11 kinase performed the most important role in stabilization of the STE5 protein. The level of STE5 protein was significantly low in the absence of STE11 kinase, suggesting essential roles of STE11 in stabilization of the STE5 protein. Immunodetection and Northern blot analyses showed that the low level of the STE5 protein in the ste11 delta mutant is not due to the level of gene expression but to that of protein stability. Measurement of relative binding affinities showed that the STE11 protein tightly interacts with the STE5 protein for its stabilization.
Kim
S H
SH
Department of Biochemistry and Molecular Biology, College of Medicine, Yonsei University, Seoul, Korea.
Lee
S K
SK
Choi
K Y
KY
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D002846:Chromatography, Affinity; D005656:Fungal Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000502:physiology*; D015870:Gene Expression / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009154:Mutation / Q000235:genetics; D010675:Pheromones / Q000502:physiology*; D011233:Precipitin Tests; D011494:Protein Kinases / Q000032:analysis / Q000235:genetics / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011994:Recombinant Proteins / Q000032:analysis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / 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; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D011994:Recombinant Proteins; C080321:STE5 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C071596:ste11 protein, S pombe; D005982:Glutathione Transferase; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C075580:FUS3 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; C078754:STE20 protein, S cerevisiae; C067018:Ste11 protein, S cerevisiae; D020929:Mitogen-Activated Protein Kinase Kinases