Updated project metadata. Over-expression of Ppz1 is deleterious for yeast cells. Recent studies in our laboratory demonstrated that the over-expression of a catalytically impaired version of Ppz1 (Ppz1R451L) is not toxic, suggesting that the excess of Ppz1 phosphatase activity was responsible for toxicity, possibly due to changes in yeast phosphoproteome. Because the molecular basis of this toxicity are still unknown, a global yeast phosphoproteomic assay was designed to gain insight into this phenomenon. To identify revelant changes cuased by Ppz1 overexpression we have constructed a strain (ZCZ01) in which the PPZ1 promoter has been replaced by the GAL promotrer. Cell grown on raffinose were shifted to galactose and samples were taken after 30, 60, 120 and 240 min and changes in proteome and phosphoproteome were analyzed by LC-MS/MS.