Phosphoproteome and Kinome Analysis: Unique Perspectives on the Same Problem

With over 500 members catalyzing an estimated 100,000 phosphorylation reactions, the kinases are among the largest and most complex families of enzymes. As phosphorylation represents the pivotal mechanism for regulation of biological processes, they are also one of the most biologically significant. Development of analytical techniques for the characterization of phosphorylation events, in particular from a global vantage point, is therefore a central priority for proteomic and cell biology researchers. There are two differing philosophies on the most appropriate perspective for global phosphorylation analysis, either through characterization of the phosphoproteome, the sub-population of proteins that undergo phosphorylation, or the kinome, the activities of the cellular protein kinases that catalyze phosphorylation. While each of these approaches strives to describe the same biological event, they employ unique experimental approaches to provide distinct, yet complimentary information. Here we review recent advances in each area, highlight their relative strengths and weaknesses, and discuss their complimentary nature for global phosphorylation analysis.