Figure 7.

Negative regulation of AMPAR-mediated current by NR2B requires synaptic localization but not PDZ domain function. A, The experimental design is identical to Figure 6 except that cells were cotransfected with NR2B siRNA as well as GFP and either wild-type or a mutated NR2B construct. Rescue constructs are shown schematically in A: the wild-type construct with intact C terminus, a PDZ mutant (ΔPDZ) that suppresses the synaptic incorporation of NR2B, and a double mutant construct (ΔPDZ/ΔAP2) that retains synaptic localization (via the Y1472A mutation) but lacks a functional PDZ domain. B, Representative ensemble mEPSC averages are shown for a nontransfected cell and cells transfected with NR2B siRNA plus the WT receptor, the PDZ mutant, or the double mutant construct. C, Cumulative distribution of mEPSCs are plotted and show that WT NR2B expression rescued the effect of NR2B-siRNA (dashed line). D, The double mutant construct ΔPDZ/ΔAP2 was also able to rescue the effect of siRNA (dashed line), although the single ΔPDZ point mutant was unable to block the effect of siRNA (thin line). E, The significance of the effects in C and D are shown comparing average mEPSC amplitude from individual cells under each transfection condition.