Additional file 4 of The Q/R editing site of AMPA receptor GluA2 subunit acts as an epigenetic switch regulating dendritic spines, neurodegeneration and cognitive deficits in Alzheimer’s disease

Additional file 4: Sup Figure 4. AMPAR surface expression and complex formulation. (a-b) BS3 crosslinking of surface AMPARs alters their molecular weight enabling the discrimination of surface-crosslinked versus intracellular-non crosslinked AMPARs. No changes were found to the ratio of surface to intracellular GluA2 in the (a) whole hippocampus or in (b) hippocampal subregions: CA1, CA3 or DG (n’s for a: WT = 7, GluA2G/G= 8, J20 = 8, GluA2G/G/J20 = 8; n’s for b: WT = 4 for CA1 and DG and 5 for CA3, GluA2G/G= 4 for CA1 and DG and 5 for CA3, J20 = 5 for CA1 and CA3 and 4 for DG, GluA2G/G/J20 = 5 for CA1 and CA3 and 4 for DG; CA1 ANOVA: F(3,14) = 1.607 p = 0.232; CA3 ANOVA: F(3,16) = 1.403 p = 0.278; DG ANOVA: F(3,12) = 1.262 p = 0.24). N’s represent averaged normalised values per immunoblot. Total protein expression of (c) GluA2 and (d) GluA2/3 in the hippocampus showed no differences between any of the genotypes (n = 6/genotype except for (c) where GluA2G/G= 5 and GluA2G/G/J20 = 5; GluA2 ANOVA: F(3,18) = 1.068 p = 0.39; GluA2/3 ANOVA: F(3,20) = 0.51 p = 0.68). (e) Co-immunoprecipitation of AMPAR subunits demonstrated none of the genotypes showed any alterations to their AMPA receptor composition within the hippocampus (unbound fraction shown; n’s: WT = 4, GluA2G/G= 3, J20 = 4, GluA2G/G/J20 = 4). For example, the first column of image in top left shows 100% of GluA1 remained in the unbound fraction when IP’ed against the IgG control, followed by