Changes in cortical TARP levels correlate with altered AMPAR regulation in NR2B null neurons, and the effect of siRNA is blocked by coexpression of a dominant-negative TARP. A, B, Relative TARP levels in WT (+) and NR2B−/− (−) cultures at 16 DIV detected by Western blot analysis using a pan-TARP antibody. C, The increase in mEPSC amplitude seen in single cultured neurons in response to transfection with NR2B-siRNA is blocked by coexpression of the TARP dominant-negative construct γ-2ΔC. D, Analysis of the cumulative data showed a significant difference in the mean amplitude of AMPA-mediated mEPSCs in neurons expressing NR2B-siRNA and γ-2ΔC compared with those expressing NR2B siRNA alone.