Fig. 1.

Global effects of Cdc28-as inhibition. (a) Addition of inhibitor to cells bearing as-form of a kinase can result in three types of phosphorylation events represented by colored arrows. The inhibitor itself can affect cellular homeostasis leading to changes in the phosphoproteome (kinase-independent). Upon inhibition of the target kinase its direct substrates will be dephosphorylated, which in turn can affect phosphorylation of other downstream targets, termed indirect substrates). (b) Yeast cells containing the cdc28-as allele were treated with vehicle or 10 μm 1NM-PP1 for 15 min. Experiments were performed in six replicates and only phosphopeptides quantified by MS in at least four replicates were considered for subsequent analysis. Significant (FDR<5%) changes were observed for 1,728 phosphosites without a clear prevalence of dephosphorylation (1,008) over phosphorylation (720) but with enrichment of CDK consensus motif among dephosphorylated phosphosites.