Figure 1.

Coexpression of TARPs differentially enlarges agonist-induced currents of GluR1(Q)flip. A, B, Glutamate-induced (A) and kainate-induced (B) responses of GluR1(Q)flip alone and in combination with each of the four TARPs were recorded from Xenopus oocytes in magnesium Ringer's solution. The application of agonists (300 μm Glu or 150 μm KA) is indicated by black bars. C, Western Blot analysis of surface membrane preparations (for details, see Methods and Materials) from Xenopus laevis oocytes expressing homomeric GluR1(Q)flip alone and in coexpression with each of the four members of the TARP family. Uninjected oocytes (N.c.) served as control for cross-reactivity of the antibodies. D, Dose–response curves for the agonist l-glutamate were determined from oocytes injected with cRNAs of GluR1(Q)flip alone and in combination with each of the four TARPs. Values are means ± SEM (n = 4–6), normalized to the maximal responses. The EC₅₀ values are given in Results.