1. The Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
2. Institute of Biomedicine, University of Eastern Finland, 70210 Kuopio, Finland
3. The Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh EH9 3BF, UK
4. Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
5. Gene Center and Department of Biochemistry, LMU-München, 81377 Munich, Germany
6. Xenobe Research Institute, P.O. Box 3052, San Diego, CA 92163-1052, USA
7. Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
8. Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada