1. Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, U.K.
2. Biochemistry Department, Dundee University, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, Scotland, U.K.
3. Division of Biochemistry and Molecular Biology, Davidson Building, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K.
4. Division of Signal Transduction Therapy, University of Dundee, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, Scotland, U.K.