1. Imperial College London, Section of Investigative Medicine; Division of Diabetes, Endocrinology and Metabolism; London W12 0NN UK
2. École Polytechnique Fédérale de Lausanne; ISIC SB, Laboratory of Protein Engineering; Av. Forel 2 1015 Lausanne Switzerland
3. Imperial College London; Section of Cell Biology and Functional Genomics, Department of Medicine; London W12 0NN UK
4. Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE); University of Birmingham; Birmingham B15 2TT UK
5. Centre for Endocrinology, Diabetes and Metabolism; Birmingham Health Partners; Birmingham B15 2TH UK
6. Current address: Max Planck Institute for Medical Research; Department of Chemical Biology; Jahnstraße 29 69120 Heidelberg Germany