FIGURE 5.

Sumoylation of NFATc1 can both suppress and enhance lymphokine induction. A, IL-2 mRNA is repressed, but RNA levels of IL-13 and IFNγ are further up-regulated upon sumoylation of NFATc1. 5 μg RNA of retrovirally infected EL-4 cells (NFATc1/C-ER, its ΔSUMO and SUMO fusion mutants) were subjected to RNase protection assay after stimulating the cells with Tm+T/I for 24 h using the mCK1 template set. Also a graph of phosphor-imaging values is given of three independent experiments where 1-6 correspond to the lanes of the autoradiography. GAPDH, glyceraldehyde-3-phosphate dehydrogenase. B, the presence of SUMO suppresses the transactivation potential of NFATc1. As in Fig. 4A, except murine EL-4 cells were transfected and plasmids expressing FLAG (F) or FLAG-SUMO1 (S) were cotransfected with those encoding NFATc1/C, K349R/K702R/K914R, or empty vector (HA) along with an IL-2-luciferase plasmid.