Figure 2

Surface expression of LRP1 and NR1/NR2B is increased in LRP1ΔNPxY2 neurons after treatment with cycloheximide. (A) Immunoblots show an increase in residual expression of LRP1 and NR1/NR2B receptors at the cell surface of LRP1ΔNPxY2 neurons after treatment with CHX. The primary neurons (DIV14) were treated with 20µg/ml CHX for 4, 6 and 8 hours and subjected to cell surface biotinylation. Biotinylated proteins were precipitated with NeutrAvidin agarose (surface). (B) The immunoblots were quantified by densitometric analysis. The intensities of the surface signals were normalized to the intensities for lysate signals (input). The values for the 4h, 6h and 8h time points were compared with respective values for 0h time point. The values for 0h time points were set as 100%. The diagrams represent the mean percent change in the residual expression of proteins at the surface of LRP1ΔNPxY2 or WT neurons after treatment with 20µg/ml CHX ± S.E.M. For the residual expression of LRP1 at the cell surface of LRP1ΔNPxY2 neurons an increase by 89% (p=0.03; n=4) after 4h, by 94% (p=0.02; n=6) after 6h and by 59% (p=0.043; n=4) after 8h was calculated. For the residual expression of NR1 by 33% (p=0.073; n=4) after 4h; by 58% (p=0.03; n=6) after 6h and by 67% (p=0.042; n=5) after 8h. For the expression of NR2B an increase by 22% (p=0.06; n=4) after 4h; by 51% (p=0.032; n=6) after 6h and by 54% (p=0.04; n=4) after 8h. The residual expression of NR2A was not significantly altered in LRP1ΔNPxY2 neurons. (C) The degradation rates of investigated proteins are not altered in LRP1ΔNPxY2 neurons. The diagrams represent the mean percent change in the expression of proteins in lysates of LRP1ΔNPxY2 or WT neurons after CHX-treatment ± S.E.M. The signal intensities of lysates were standardized to actin. * p<0.05, Student´s paired t-test.