(A) QD-BDNF internalization assay on HEK293T cells co-transfected with expression vectors encoding the BDNF receptor TrkB (Red), together with shRNA constructs (Green) and/or wild-type paxillin, as indicated. Histograms showing that co-transfection of paxillin shRNA C and shRNA D significantly reduced QD-BDNF internalization (as reflected by an ~8-fold reduction in the quantity of intracellular QD-BDNF). Data represent means ±SEM (n ≥ 3 independent experiments, 26–52 cells for each set of experiments; compared to scrambled shRNA control; ***p<0.001; ANOVA with Dunnett’s post hoc test). (B) Similar to A, except cells were pre-incubated with or without the dynamin inhibitor dynasore (50 μM, 30 min). Histograms show that dynamin is required for paxillin to promote QD-BDNF internalization. Data represent means ±SEM (n ≥ 3 independent experiments, 21–58 cells for each set of experiments; compared to GFP control; ***p<0.001; ANOVA with Dunnett’s post hoc test).