Figure 1

LRP1 and NMDA receptor subunits NR1/NR2B are increased at the surface of cortical LRP1ΔNPxY2 neurons. (A) Representative immunoblots demonstrate an increase in surface expression of LRP1 and NMDA receptor subunits NR1/NR2B in primary LRP1ΔNPxY2 neurons. The surface expression of NR2A is not altered. Primary cortical WT or LRP1ΔNPxY2 neurons were subjected to cell surface biotinylation prior to lysis. Biotinylated proteins were precipitated with NeutrAvidin agarose and analyzed by SDS-PAGE and Western blot (surface). As input controls 15µg of entire cell lysates proteins were used (input). (B) The protein expression at the cell surface was quantified by densitometric analysis. The intensities of the surface signals were normalized to the intensities of lysate signals (input). The calculated values for WT were set as 100%. The scale bars represent the mean percent change in the expression of proteins at surface of LRP1ΔNPxY2 neurons compared with WT controls ± S.E.M. for the expression of LRP1 at the surface of LRP1ΔNPxY2 neurons an increase by approx. 90% (p=0.01; n=4); for NR1 and NR2B an increase by approx. 60% (p=0.007; n=4) and by approx. 44 % (p=0.04; n=4) respectively. The signal intensities of lysates were standardized to the signal intensities of actin. * p<0.05, Student´s paired t-test. (C) Representative immunoblots demonstrate unaltered expression rates of synaptophysin and PSD95 in neuronal cell lysates or in brain homogenates of LRP1ΔNPxY2 or WT animals. (D) The densitometric analysis of multiple Western blots demonstrated any significant alterations in expression of synaptophysin or PSD95 in cell lysates or brain homogenates of LRP1ΔNPxY2 mice. The scale bars represent the mean percent change in the expression of synaptophysin or PSD95 in neuronal lysates or brain homogenates derived from LRP1ΔNPxY2 animals compared with WT controls ± S.E.M. The signal intensities of lysates were standardized to the signal intensities of actin. n=5.