Phosphoproteomic Effects of Acute Depletion of PP2A Regulatory Subunit Cdc55

Protein phosphatase regulatory subunits are increasingly recognized as promising drug targets. In the absence of an existing drug, inducible degradation provides a means of predicting candidate targets. We here employed auxin-inducible degradation of S. cerevisiae PP2A regulatory subunit Cdc55 in combination with quantitative phosphoproteomics. A prevalence of hyperphosphorylated phosphopeptides and enrichment of proteins containing the PP2A consensus sequence indicates that the approach successfully identified direct PP2A-Cdc55 targets. PRM follow up of DDA-results confirmed that vacuolar amino acid transporters are among the proteins most strongly affected by Cdc55 depletion.