Fig. 8.

Thr/Val and Ala/Leu mutations of GluK2 abolish kainate-induced responses of both homomeric GluK2 and heteromeric GluK2/GluK5 receptors. Wild type (WT) or mutant (GluK2-T659V, GluK2-A487L, GluK2-S689N/N690S, GluK2-A487T) GluK2 was expressed as homomer or heteromer with WT GluK5 in HEK293 cells as indicated. Following incubation with fura-2-AM, 25 µM kainate-induced increase in [Ca²⁺]_i was measured in GFP positive transfected cells. GluK2 mutants with impaired LBD (GluK2-T659V and GluK2-A487L; red bars) have significantly fewer cells that respond to kainate with an increase in [Ca²⁺]_i compare to GluK2-WT or subunit conversion mutants (GluK2-S689N/N690S, GluK2-A487T; blue bars). Co-expression of GluK5-WT has not altered the kainate-evoked responses of LBD mutant GluK2 subunits. Data are mean ± SEM (n = 3), *p < 0.05, ***p < 0.005 mutants compared to WT, Student’s t test. (Color figure online)