Thousands of proteins in a human cell are regulated by phosphorylation — the addition of small chemical groups to the proteins’ amino acids by enzymes called protein kinases. This process is known as phosphorylation. Abnormal protein phosphorylation has been implicated in a number of diseases, notably cancer and degenerative diseases like Parkinson’s and Alzheimer’s. Some 90,000 sites of phosphorylation on serine and threonine amino acids have been identified, but it hasn’t been known which of more than 300 protein serine or threonine kinases are responsible. In a new study, researchers at Weill Cornell Medicine and Dana-Farber Cancer Institute purified and characterized the substrate specificity of essentially all the human protein-serine/threonine kinases and developed a computational method to identify the kinases capable of phosphorylating every known phosphorylation site in the human serine/threonine proteome.
