FIG. 4.

Phosphorylation of NFATc1-α in vivo. (A) NFATc1-α was coexpressed with MKK7 plus JNK1 in COS cells. The effect of replacement of Ser¹¹⁷ and Ser¹⁷² with Ala residues was investigated. Cell lysates were examined by protein immunoblot analysis by sequentially probing with anti-phospho-NFATc1-α and anti-NFATc1. A nonspecific band was detected by the phospho-NFATc1-α antibody immediately above the NFATc1-α band. (B) NFATc1-α was coexpressed without (−) and with (+) the JNK inhibitor JIP-1 in COS cells. The cells were treated without (−) and with (+) UV-C radiation (80 J/m²) and harvested after 30 min. The effect of replacement of the JNK phosphorylation sites (Ser¹¹⁷ and Ser¹⁷²) with Ala was examined. The NFATc1-α proteins were detected by protein immunoblot analysis by sequentially probing with anti-phospho-NFATc1-α and anti-NFATc1.