1. Department of Molecular Biology and Functional Genomics
2. Italian Institute of Technology Network Research, Unit of Molecular Neuroscience, San Raffaele Scientific Institute, 20132 Milano, Italy
3. Università Vita-Salute San Raffaele, 20132 Milano, Italy
4. Fondazione Italiana per la Ricerca sul Cancro Institute of Molecular Oncology, 20139 Milano, Italy
5. Laboratory for Fluorescence Dynamics, University of California, Irvine, Irvine 92697, CA