Phosphopeptide proteomics

Protein phosphorylation on serine, threonine or tyrosine residues, can regulate protein-protein interactions via specific binding to the phospho-residues. In the February 21 Science, Andrew Elia and colleagues describe a proteomic screen designed to isolate novel phospho-binding proteins (Science, 299:1228-1231, February 21, 2003).

Elia et al. created a library of biased, immobilized partially degenerate phosphopeptides and used them as bait to screen binding proteins. They tested the technique with peptides resembling cyclin-dependent kinase targets and isolated the mitotic kinase Plk1 (polo-like kinase 1). They identified the phospho-peptide binding domain and tested binding specificities. The phospho-binding domain of Plk1 is important for localization to the centrosome during mitosis.