Changes in synaptic ProSAP/Shank levels after Aβ treatment are not linked to transcriptional regulation. Western blots of P2 membrane fractions from hippocampal neurons cultured for 15 DIV and then treated for 6 and 24 h with Aβ1-40. A) Compared to untreated cells at time-point 0, a significant decrease in the amount of ProSAP2/Shank3 and Shank1 could be detected after 6-24 h of Aβ treatment (right panel). Homer1 and PSD-95 levels also show a decrease of protein levels after 24 h. Lysates from 3 independent experiments were quantified via Western Blot analysis by measuring the integrated density. The values were normalized against β-III Tubulin and 0 h was set to 100%. B) Quantitative RT-PCR was performed for ProSAP2/Shank3 and Shank1 after Aβ1-40 treatment. mRNA was isolated from hippocampal neurons (DIV15) at time-point 0 and after 1, 6, and 24 h. The mean ratio between treated and untreated control neurons from three independent experiments is shown. No significant changes in transcription levels can be seen.