New tools for quantitative phosphoproteome analysis

Recent advances in analytical methods, particularly in the area of mass spectrometry, have brought the field of proteomics to the forefront in biological science. The ultimate goal of proteomics-to characterize proteins expressed within a cell under a specific set of conditions-is daunting due to the complexity and dynamic nature the of protein population within the cell. While much of the effort has focused on developing methods to identify expressed proteins, the identification of post-translational modifications is equally important for comprehensive proteome characterization. Of all the known post-translational modifications, phosphorylation arguably plays the largest role in the context of cellular homeostasis. This review discusses some of the recent progress made in the development of techniques not only to identify, but also to quantitatively determine sites of phosphorylation.