NF-AT-but not NF-ΚB- or AP-1-driven transcription is strongly reduced by Lptn.

(A) JA16 cells were electroporated with p5xAP-1, p3xNF-AT, or p2xNF-ΚB-Fluc constructs, activated with the indicated stimuli for overnight. Luciferase expression was measured as described above. The increases in RLU in CD3-stimulated cells as compared with unstimulated cells were approximately of 10-, 1.5-, and 20-fold for NF-ΚB, AP-1, and NF-AT, respectively. Data are representative of at least 4 independent experiments. (B) NF-ATc but not NF-ATp is able to overcome the Lptn-mediated inhibition of IL-2 promoter-driven transcription. JA16 cells were cotransfected with 7.5 μg of pIL-2-FLuc and either the empty pBluescript SK as control (vector), NF-ATp, or NF-ATc/C cDNA expression vectors at the indicated doses. Relative luciferase activity (RLU) was measured in cultures activated overnight with the indicated stimuli, as explained in the legend of Figure 4. Data represent mean values with SD between brackets (ND = not determined) of 5 independent experiments, except for CD3+Lptn+anti-Lptn, where 2 and 1 experiments were done, respectively, with NF-ATc and NF-ATp.