(A) Empty vector cDNAs or GFP-LxVP cDNAs were transfected into HEK293T cells. The HEK293T cells were pretreated with DMSO or quercetin for 12 h and then subjected to co-precipitation and western blot analysis. (B) Six μg of empty vector cDNAs or NFATc3 (3-407)-GFP were transfected into HEK293T cells. The cells were stimulated with PMA (50 ng/ml) plus ionomycin (1 μM). CsA (10 μM) was used as a positive control. The blot shows the expression of GFP-NFAT in total lysates, and also indicates the positions of phosphorylated and dephosphorylated proteins. (C, D, E) Quercetin inhibits NFAT-driven gene expression. Total mRNA was extracted 5 h after stimulation with ionomycin and PMA. The mRNA levels of IL-2 (C), IL-10 (D) and IFN-γ (E) were quantified by qRT-PCR. The mRNA levels of the control group were set at 100%. The data are shown as means ± SEM of three independent experiments. ** p < 0.01, *** p < 0.001 compared with the PMA + ionomycin group.