NMR-based investigation into protein phosphorylation.

Protein phosphorylation is a major switch mechanism for cell signaling process regulation within eukaryotic cells. Abnormal phosphorylation is either a cause or consequence of human diseases. It is imperative to comprehensively delve into the relationship between phosphorylation events and cell signaling transduction. NMR spectroscopy, a potent tool for monitoring protein phosphorylation events, is applicable for identifying the phospho-sites, quantifying the kinetic rate, discovering kinase/phosphatase inhibitors and delineating phosphorylation crosstalk with other post-translational modifications. Here, we decipher the recent progress in the investigation of eukaryotic protein O-phosphorylation by NMR spectroscopy. We focus specifically on the dynamic establishment of O-phosphorylation and its role in the cell signaling processes. Simultaneously, we positively propose a strategy for the investigation of acid-labile and "high-energy" N-phosphorylation by NMR spectroscopy. We expect that the strategy could enrich the investigation of protein N-phosphorylation.