Figure 2. FK506 (tacrolimus) binding protein 51 overexpression increases protein levels of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), activated NF-κB, and decreased protein levels of inhibitory molecule, IKappaB (IκB). A: FK506 Binding Protein 51 (FKBP51) overexpression significantly increased NF-κB p65 and phospho NF-κB p65 protein levels while significantly decreasing IκBα protein levels. The 661w neuronal cell culture—stably transfected with an FKBP51 expression vector—increased FKBP51 protein levels fivefold, compared to the 661w neuronal cell culture stably transfected with the parental empty vector. (-) represents stably transfected empty vector control cells and (+) represents stably transfected FKBP51 overexpression cells. B, C: The increase in FKBP51 expression caused a significant increase in protein levels of NF-κB p65 and activated NF-κB p65 (NF-κB p65: n=6, *p=0.002; phospho NF-κB p65: n=6, *p=0.002). D: The increase in FKBP51 expression caused a significant decrease in protein levels of IκBα (IκBα: n=3, *p=0.044). The loading controls were β-tubulin for IκBα and NF-κB p65, while GAPDH was used for FKBP51 and for activated NF-κB p65. Significance was obtained through one-way ANOVA (ANOVA) and the Mann–Whitney test. Error bars represent SEM.