1. Department of Neurology and Neurobiology and
2. Immunology Program, Sloan-Kettering Institute for Cancer Research, New York, New York, USA;
3. Department of Cell and Developmental Biology, Weill-Cornell Medical School, New York, New York, USA;
4. The Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway; and
5. Department of Chemistry, Michigan State University, East Lansing, Michigan, USA