1. Departament de Biologia Cellular, Facultat de Medicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Universitat de Barcelona, Casanova 143, 08036 Barcelona, Spain.
2. Institute for Molecular Bioscience, Centre for Microscopy and Microanalysis and School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia.
3. Max-Plank-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.