Quantifying proteomes and their post-translational modifications by stable isotope label-based mass spectrometry.

Stable isotope labeling coupled with mass spectrometry has revolutionized the scope and impact of protein expression studies. Label incorporation can occur metabolically or chemically, and each method bears specific strengths and weaknesses. Quantitative proteomics confidently identifies specific interactions between proteins and other biological species, such as nucleic acids and metabolites. Extending label-based methods to phosphorylation-modified forms of proteins enables the construction of signaling networks and their temporal responses to stimuli. The integration of multiple data types offers systems-level insight on coordinated biological processes. Finally, the development of methods applicable to tissue quantification suggests the emerging role of label-based, quantitative mass spectrometry in translational science.