title: Formation of subnuclear foci is a unique spatial behavior of mating MAPKs during hyperosmotic stress.
abstract: The assembly of signaling components and transcription factors in ordered subcellular structures is increasingly implicated as an important regulatory strategy for modulating the activity of cellular pathways. Here, we document the inducible formation of subnuclear foci formed by two mitogen-activated protein kinases (MAPKs) in Saccharomyces cerevisiae upon hyperosmotic stress. Specifically, we demonstrate that activation of the hyperosmotic stress response pathway induces the mating pathway MAPK Fus3 and the filamentation pathway MAPK Kss1 to form foci in the nucleus that are organized by their shared downstream transcription factor Ste12. Foci formation of colocalized Ste12, Fus3, and Kss1 requires the kinase activity of the hyperosmotic response MAPK Hog1 and correlates with attenuated signaling in the mating pathway. Conversely, activation of the mating pathway prevents foci formation upon subsequent hyperosmotic stress. These results suggest that Hog1-mediated spatial localization of Fus3 and Ste12 into subnuclear foci could contribute to uncoupling the pheromone and osmolarity pathways, which share signaling components, under high-osmolarity conditions.
authors: Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA 94158, USA.
authors: Simon E
authors: SE
authors: Vidal
authors: David
authors: D
authors: Pincus
authors: Jacob
authors: J
authors: Stewart-Ornstein
authors: Hana
authors: H
authors: El-Samad
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009997:Osmotic Pressure; D010675:Pheromones / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D010675:Pheromones; C489241:STE12 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C075580:FUS3 protein, S cerevisiae; C088589:HOG1 protein, S cerevisiae; C541984:KSS1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases