[Methods of analysis of protein phosphorylation]

Phosphorylation and dephosphorylation play a fundamental role in most signaling pathways, as these processes can directly regulate various aspects of protein function. It is estimated that there are about 100,000 potential phosphorylation sites in proteins encoded by the human genome and about 30-50% of all proteins in the cell can be phosphorylated, which is directly related to the functions they perform. To determine whether a given protein is phosphorylated, any changes in its mobility caused by this modification are examined during PAGE electrophoresis. Concurrently, tandem mass spectrometry (MS/MS) allows to identify specific phosphorylation sites. The next step involves the prediction (using in silico analysis) which kinases can phosphorylate a specific site in the given protein. Then, in order to verify the information obtained from databases, in vitro and/or in vivo experiments are carried out.