1. Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences, Sir James Black Complex, University of Dundee, Dundee DD1 5EH, Scotland, U.K.
2. MRC Protein Phosphorylation Unit, College of Life Sciences, Sir James Black Complex, University of Dundee, Dundee DD1 5EH, Scotland, U.K.
3. College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K.
4. Oregon Stem Cell Centre, Oregon Health & Science University, Portland, OR 97239-3098, U.S.A.