1. School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
2. GSK/IMCB Group, Institute of Molecular and Cell Biology, Proteos, 61 Biopolis Drive, Singapore 138673, Republic of Singapore
3. Department of Molecular Neuroscience, Institute of Neurology, University College London, 1 Wakefield Street, London, WC1N 1PJ, UK