Mining for Protein Kinase Substrates: Integration of Biochemistry, Genetics and Proteomics

The inhibition of protein phosphorylation is proving to be a powerful therapeutic approach to treat a number of disorders. As more protein kinase inhibitors are developed, critical issues of drug and target specificity must be addressed. While a remarkable amount of information exists for the regulation of protein kinase function, relatively little is known about the substrates they phosphorylate. Classical protein kinase substrate identification approaches have been hampered largely due to high background phosphorylation in cellular lysates and the laborious methods required identifying and purifying both the protein kinases and their substrates. Recent advances in biochemistry, bioinformatics and proteomics have addressed many of these issues. A particularly powerful method to identify direct protein kinase substrates combines standard proteomics with a unique chemical genetics approach. Identification of new protein kinase substrates by such chemical-genetic and other emerging technologies may provide the next generation of drug targets for multiple therapeutic areas.