Figure 2.

The NFAT1 ΔCC′QQ-EE mutant cannot transactivate from dimer sites, but conserves full activity on NFAT–AP1 composite sites. Jurkat T cells were cotransfected with reporter plasmids in which the expression of the luciferase gene was driven by enhancers containing tandem κB-like sites (A), composite NFAT–AP-1 sites (B), or NFAT monomer binding sites (C), as well as an empty control vector or plasmids expressing an HA-tagged constitutively active NFAT1 (WT) or the ΔCC′QQ-EE dimerization mutant protein. Cells were then treated with CsA, CsA and ionomycin (A and C), or CsA+ionomycin+PMA (B) for 8 h, and luciferase activity was measured. Normalized values (to the activity of the stimulated cells expressing WT NFAT1) are presented from three to eight independent experiments. Error bars are the SEM. (inset) Immunoblot of NFAT1 WT and ΔCC′QQ-EE expression in transfected cells using an anti-HA antibody.