1. Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina; Universitat de Barcelona; C/ Casanova, 143 08036 Barcelona Spain
2. Current address: Vlaams Instituut voor Biotechnologie (VIB), Centre for the Biology of Disease and KU Leuven, Department of Human Genetics; Campus Gasthuisberg; 3000 Leuven Belgium
3. Institute of Structural and Molecular Biology, Division of Biosciences; University College London; London WC1E 6BT UK
4. Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Barcelona Spain