1. Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
2. Cancer Centrum Karolinska, Karolinska Institutet, SE-171 76 Stockholm, Sweden
3. Institute for Biochemistry and Molecular Biology and BIOSS (Centre for Biological Signaling Studies), University of Freiburg, D-79104 Freiburg, Germany
4. Zentrallabor für Proteinanalytik, Adolf-Butenandt Institut, LMU München, D-80336 München, Germany