1. Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, the Netherlands.
2. Department of Medicine, Center for Molecular Medicine, Karolinska University Hospital Solna and Karolinska Institutet, 171 76 Stockholm, Sweden.
3. Department of Molecular and Cell Biology, Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Cientificas, Campus Universidad Autonoma de Madrid, 28006 Madrid, Spain.
4. MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
5. Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.