Enrichment strategies for phosphoproteomics: state-of-the-art

Abstract

Protein phosphorylation is a key regulator in many biological processes, such as homeostasis, cellular signaling and communication, transcriptional and translational regulation, and apoptosis. The defects in this tightly controlled reversible post-translational modification have been described to contribute to genesis and progression of various diseases, emphasizing the importance of a systematic research of this phenomenon. Although considerable effort has been devoted to improving the analysis of phosphorylation by mass spectrometry, which is currently the method of choice to study protein phosphorylation, the detection and identification of phosphorylation sites remains challenging because of the low abundance and low ionization efficacy of phosphoproteins in comparison with nonphosphorylated proteins. To overcome this obstacle, different enrichment strategies for phosphorylated peptides/proteins have been established and optimized for subsequent mass spectrometry analysis. In this review, we will give an overview of the methods currently available for the enrichment of phosphorylated proteins and peptides including immunoprecipitation, chemical derivatization and affinity enrichment techniques.

Keywords

• metal oxide affinity chromatography
• phosphopeptide enrichment
• phosphoproteomics