To hear Tony Hunter tell the story, his discovery of tyrosine phosphorylation was nothing more than a happy accident. It was 1979, and researchers had known for decades that protein kinases were involved in regulating cell growth, proliferation, and metabolism. But, as far as everyone thought, kinases phosphorylated their target proteins only on serine or threonine residues, the only modified amino acids that had been detected.
Enter Tony Hunter. An assistant professor at the Salk Institute for Biological Studies, Hunter was studying how certain tumor viruses - in particular, polyomavirus and the Rous sarcoma virus - transform human cells. Although researchers had identified the key proteins involved, that is, middle T antigen for polyomavirus and Src for Rous, they weren't sure what those proteins did. "Two groups had reported a kinase activity associated with the viral Src protein," recalls Hunter: Marc Collett and Ray Erikson, then at the University of ...
