Evolutionary Protein Phosphorylation In Yeast Species

Protein phosphorylation is a key mechanism of cell signaling and regulation of protein function. Once a protein becomes phosphorylated, its functional state is modified (e.g. from inactive to active) and the signal that was originally being transmitted is changed. To determine if protein phosphorylation is evolutionarily conserved, we examined protein phosphorylation events in 9 different yeast species. We obtained and analyzed yeast peptides to identify proteins and then enriched for phosphopeptides to locate phosphorylation sites. Yeast peptides and phosphopeptides were detected via mass spectrometry and analyzed using MaxQuant, a software program that compares peptide and phosphopeptide mass spectra to a database to identify the proteins. We expect to see that yeast species sharing a common ancestry will have similar phosphorylation sites, whereas yeast species that are not highly related will show different sites of phosphorylation.  We believe that studying protein phosphorylation in different yeast species will provide insights to similar phosphorylation events that may occur in humans.