1. Department of Medicine I and Clinical Chemistry, University Hospital of Heidelberg , INF 410 , Heidelberg , Germany
2. Institute of Molecular Genetics, Academy of Sciences of the Czech Republic , CZ-14300 Prague , Czech Republic
3. Institute of Molecular Cancer Research, University of Zurich , 8057 Zurich , Switzerland
4. German Center of Diabetes Research (DZD) , Neuherberg , Germany
5. European Molecular Biology Laboratory, Advanced Light Microscopy Facility , Heidelberg , Germany
6. Institute for Immunology, University Hospital of Heidelberg , INF 305 , Heidelberg , Germany