Norbin localizes to and accumulates in dendritic spines of hippocampal neurons. A) Confocal images of neurons showing immunolabeling of Norbin and PSD-95. Norbin is localized in the soma and dendrites. B) A higher magnification shows that Norbin is localized to dendritic spines. C-D) Confocal images of neurons co-transfected with Norbin-GFP and TagRFP showing Norbin accumulated in spines (arrows). E) An intensity plot of the line in D shows the relative accumulation of Norbin-GFP in spines. F-I) Fluorescent recovery after photobleaching (FRAP) experiments in neurons co-transfected with Norbin-GFP and mCherry. F) In dendrites, there was no difference in recovery half times between Norbin and mCherry (tNorbin = 3.7 ± 0.2 s, tmCherry = 3.2 ± 0.2 s, mean ± SEM, p > 0.5, Kruskal-Wallis test, n = 11). G, H) In spines, recovery half times were significantly different between Norbin and mCherry (tNorbin = 8.0 ± 0.4 s and tmCherry = 1.9 ± 0.2 s, mean ± SEM, ***p < 0.0001, Kruskal-Wallis test, n = 59). I) Norbin-GFP had a longer half time of recovery in spines than in dendrites (8.0 ± 0.4 s vs. 3.7 ± 0.2 s, mean ± SEM, *p < 0.05, Kruskal-Wallis test).