Fig. 8.

Half-life of cell surface GluR1 in spinal cord neuronal cultures at day 4 and day 11 in vitro. Plates of spinal cord neurons were biotinylated at day 4 and day 11 and recultured for 0–24 hr, at which time cell extracts were harvested, sonicated, and frozen. Subsequently, these samples were thawed and incubated with streptavidin-linked beads, and the streptavidin-precipitated material was loaded onto gels (A). A standard curve including serial dilutions of the t = 0 streptavidin-precipitated material was included on each gel for purposes of quantitation. After transfer, gels were probed with the C-GluR1 antibody. In B, the natural log of the percent of remaining surface GluR1 was plotted against time, and half-lives were calculated from the regression slopes of the resulting lines. The results of the experiment in A are shown.