Fig. 6.

Deletion of the GluR1 4.1 binding region reduces surface expression of GluR1. The membrane proximal region in the GluR1 C terminus is important for receptor surface expression. COS cells were transfected with pRK5 (Mock), GluR1*812 (R1*812), or GluR1*823 (R1*823). Surface expression of GluR1 was determined by biotinylation, as described in Materials and Methods. Samples from total cell lysates (Total) and biotinylated samples (PM) were analyzed for GluR1. For quantitation, the signals from biotinylated samples were divided by the total GluR1 signals to obtain the ratio of surface expression for GluR1*823 (R1*823) and GluR1*812 (R1*812). The ratio of surface expression of GluR1*812 was normalized to that of GluR1*823 to obtain the relative value of surface expression. n = 3. The error bar indicates SEM.