Fig. 1.

Design and characterization of GluA2-CFP/YFP fusion constructs. (A) Surface representation of the X-ray crystal structure of the GluA2 receptor (Protein Data Bank ID code 3KG2) (6) with domains (ATD, LBD, and TMD) indicated. Each of the four subunits is highlighted in a different color. To the Right is shown a ribbon representation of the structure of a single GluA2 subunit (green) with the structures of CFP (blue) and YFP (yellow) shown to scale. The insertion sites I0, I3, I6, and I10 are highlighted in magenta. (B) Schematic overview of GluA2 subunit topology and FP insertions. (C) Confocal micrographs of CFP (Left) and YFP (Right) fluorescence in HEK293 cells transfected with the GluA2-CFP/YFP fusion constructs. (D) Summary of amplitudes of membrane currents evoked by glutamate (0.1 mM) in Xenopus oocytes expressing GluA2-CFP/YFP constructs held at a membrane potential of −60 mV (Materials and Methods). Data represent mean ± SEM for six to 12 oocytes. A summary of relative emission intensities for CFP (E) and YFP (F) in suspensions of transfected HEK cells transfected with GluA2-CFP/YFP constructs is provided. Data are shown normalized to the intensity measured for GluA2-0Y-10C and represent the mean ± SEM of three independent transfection experiments.