The post-translational modification (PTM) of tyrosine residues by the reversible addition of a phosphate group is a powerful signaling switch in a wide range of cellular events (1). Many growth factors act through receptor tyrosine kinases and subsequent phospho-tyrosine/serine/threonine cascades to control cell proliferation, migration, and adhesion (2). The deregulation of tyrosine phosphorylation is known to underlie many diseases including cancers and many of the 90 human tyrosine kinases are targets for the development of anti-cancer therapeutics (3). Some well known tyrosine kinase inhibitors include GleevecTM approved for the treatment of chronic myeloid leukemia (CML) and IressaTM and TarcevaTM for the treatment of non small cell lung cancer (NSCLC) (3).
Because of the critical importance of tyrosine phosphorylation in normal and aberrant cell functions, there is great interest in identifying the phosphotyrosine profile of single proteins, protein pathways and whole cells under a variety of conditions and dynamic states. Phosphotyrosine antibodies are a powerful tool in helping elucidate the role of this PTM in cellular functions.
