SOLUTION STRUCTURE OF THE CORE NFATC1 DNA COMPLEX/

The nuclear factor of the activated T cell (NFAT) family of transcript ion factors regulates cytokine gene expression by binding to the promo ter/enhancer regions of antigen-responsive genes, usually in cooperati on with heterologous DNA-binding partners. Here we report the solution structure of the binary complex formed between the core DNA-binding d omain of human NFATC1 and the ARRE2 DNA site from the interleukin-2 pr omoter. The structure reveals that DNA binding induces the folding of key structural elements that are required for both sequence-specific r ecognition and the establishment of cooperative protein-protein contac ts. The orientation of the NFAT DNA-binding domain observed in the bin ary NFATC1-DBD/DNA complex is distinct from that seen in the ternary NFATC2/AP-1/DNA complex, suggesting that the domain reorients upon for mation of a cooperative transcriptional complex.