Comparative proteome analysis of Saccharomyces cerevisiae: a global overview of in vivo targets of the yeast activator protein 1.
BACKGROUND
The activity of the yeast activator protein 1 (Yap1p) increases under stress conditions, which leads to enhanced transcription of a number of genes encoding protective enzymes or other proteins. To obtain a global overview of changes in expression of Yap1p-targeted proteins, we compared a Yap1p-overexpressing transformant with a control transformant by triplicate analysis of the proteome using two-dimensional gel electrophoresis (2-DE). Proteins of interest were identified using MALDI-MS or LC-MS/MS.


RESULTS
The relative quantities of 55 proteins were elevated significantly upon overexpression of Yap1p, and most of these proteins were found to have a Yap1p-binding site upstream of their coding sequences. Interestingly, the main metabolic enzymes in the glycolysis and pyruvate-ethanol pathways showed a significant increase in the Yap1p-overexpressing transformant. Moreover, a comparison of our proteome data with transcriptome data from the literature suggested which proteins were regulated at the level of the proteome, and which proteins were regulated at the level of the transcriptome. Eight proteins involved in stress response, including seven heat-shock and chaperone proteins, were significantly more abundant in the Yap1p-overexpressing transformant.


CONCLUSIONS
We have investigated the general protein composition in Yap1p-overexpressing S. cerevisiae using proteomic techniques, and quantified the changes in the expression of the potential Yap1p-targeted proteins. Identification of the potential Yap1p targets and analysis of their role in cellular processes not only give a global overview of the ubiquitous cellular changes elicited by Yap1p, but also provide the framework for understanding the mechanisms behind Yap1p-regulated stress response in yeast.
Department of Chemistry, Umeå University, Sweden.
He
H
Jun
Thomas
T
Kieselbach
Leif J
LJ
Jönsson
D015153:Blotting, Western; D015180:Electrophoresis, Gel, Two-Dimensional; D015966:Gene Expression Regulation, Fungal; D053858:Metabolic Networks and Pathways; D020543:Proteome / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D018808:Transcription Factor AP-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D059467:Transcriptome / Q000235:genetics; D014170:Transformation, Genetic; D015854:Up-Regulation / Q000235:genetics
D020543:Proteome; D029701:Saccharomyces cerevisiae Proteins; D018808:Transcription Factor AP-1; D014157:Transcription Factors; C086677:YAP1 protein, S cerevisiae