The cell wall integrity (CWI) pathway of the model organism Saccharomyces cerevisiae has been thoroughly studied as a paradigm of mitogen-activated protein kinase (MAPK) pathway. It consists of a classic MAPK module comprising the Bck1 MAPKKK, two redundant MAPKKs, Mkk1 and Mkk2, and the Slt2 MAPK. This module is activated under a variety of stimuli related to cell wall homeostasis by Pkc1, the only member of the protein kinase C family in budding yeast. Stable Isotope Labeling of Amino acids in cell Culture (SILAC)-based quantitative phosphoproteomics is a powerful tool to globally study protein phosphorylation. Here we report an analysis of the yeast phosphoproteome upon overexpression of a PKC1 hyperactive allele, which specifically activates CWI MAPK signaling in the absence of external stimuli. We found 82 phosphopeptides originated from 43 proteins that showed enhanced phosphorylation in these conditions. The MAPK S/T-P target motif was significantly over-represented in these phosphopeptides. Hyperphosphorylated proteins provide putative novel targets of the Pkc1-CWI pathway involved in diverse functions, such as the control of gene expression, protein synthesis, cytoskeleton, DNA repair and metabolism. Remarkably, five components of the plasma membrane-associated protein complex named eisosome were found among the up-regulated proteins. We show here that Pkc1-induced phosphorylation of the eisosome core components Pil1 and Lsp1 was not exerted directly by Pkc1, but involved signaling through the Slt2 MAPK module.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|