1. Department
of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, United States
2. Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, 360 Longwood Avenue, Longwood Center LC-2209, Boston, Massachusetts 02115, United States
3. MRC
Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1
5EH, Scotland, United Kingdom