Fig. 3 | Communications Biology

Fig. 3

From: Coupling of a viral K+-channel with a glutamate-binding-domain highlights the modular design of ionotropic glutamate-receptors

Fig. 3

Functional characterization of the GluATCV chimera. a Glu responses of GluA1 and GluATCV* upon expression in Xenopus oocytes. Traces of Glu responses of GluA1 and GluATCV* with different concentrations of glutamate. The bars show the duration of the application of the corresponding concentration. b Glutamate dose–response curves recorded from GluA1 (squares) or GluATCV* (circles) expressing oocytes. Both show a similar EC50 value of 5.8 ± 1.2 and 4.0 ± 0.4 µM for GluATCV* and GluA1, respectively. c CNQX-inhibition curve of GluA1 and GluATCV* at the EC50 value of glutamate. The CNQX IC50 is 4.4 ± 0.9 and 2.0 ± 0.1 µM for GluATCV* and GluA1, respectively. d Plot of the reversal voltages of the GluA1 and GluATCV* receptors against the extracellular K+ concentration. Reversal voltages were estimated by current–voltage (I–V) recordings in different ringer solutions containing 10, 50, 100, and 150 mM K+. The proportional shift of the reversal voltage as a function of the concentration of K+ in the extracellular medium with a slope of 59.3 ± 4.9 for the GluATCV* and 3.9 ± 4.7 for GluA1 confirms a high selectivity for K+ over Na+ in the GluATCV* channel

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