NSF knockdown results in decreased uptake function of SERT in HEK293-hSERT cells. Fluorescent substrate uptake activity was significantly decreased in HEK293-hSERT cells transfected with siRNAs targeting specific NSF sequences, siRNA-1 (◆) and siRNA-2 (▲), compared with negative control (○) (control vs siRNA-1 P < 0.01, and control vs siRNA-2 P < 0.001, one-way repeated measures ANOVA with Tukey’s post hoc test). Nonspecific uptake was determined in the presence of 10 μM fluoxetine (■). Data are expressed as a percentage of the control level. Each point corresponds to the mean ± standard deviation, n = 8. siRNA, small interfering RNA.