Identification of specific
protein phosphorylation sites provides predicative signatures of cellular activity and specific disease states such as
cancer, diabetes,
Alzheimer disease, and
rheumatoid arthritis. Recent progress in
phosphopeptide isolation technology and tandem mass spectrometry has provided the means to identify thousands of phosphorylation sites from a single biological sample. These advances now make it possible to profile global changes in the phosphoproteome at an unprecedented level. However, although this technology is generating a wealth of information, there is currently no efficient means to identify
phosphoprotein signatures shared among large
phosphoprotein databases. Identification of common
phosphoprotein signatures found in biologically relevant systems and their conservation throughout evolution would provide valuable insight into mechanisms of signal transduction and cell function. Here we describe the development of a computational program (PhosphoBlast) that can rapidly match thousands of
phosphopeptides that share phosphorylation sites within and across species. PhosphoBlast analysis of several large
phosphoprotein datasets from the literature revealed common phosphorylation signatures shared across diverse experimental platforms and species. Moreover PhosphoBlast is a powerful analysis tool to identify specific phosphosite mutations. Comparison of the mouse and human phosphoproteomes revealed more than 130 specific phosphoamino
acid mutations, some of which are predicted to alter
protein function. Further analysis revealed that known phosphorylated
amino acids are more evolutionally conserved than the Ser/Thr/Tyr
amino acids not known to be phosphorylated. Together our results demonstrate that PhosphoBlast is a versatile mining tool capable of identifying related phosphorylation signatures and phosphoamino
acid mutations among complex proteomics datasets in a highly efficient and accurate manner. PhosphoBlast will aid in the informatics analysis of the phosphoproteome and the identification of
phosphoprotein biomarkers of disease.