NFATC1 is a member of the NFAT family of proteins which are Ca2+/calcineurin-responsive transcription factors primarily recognized for their central roles in T lymphocyte activation and cardiac valve development. NFAT consists of at least two components: a preexisting cytosolic component that translocates to the nucleus upon T-cell receptor (TCR) stimulation, and an inducible nuclear component. Proteins belonging to the NFAT family of transcription factors play a central role in inducible gene transcription during immune response. The product of NFATC1 is an inducible nuclear component and functions as a major molecular target for the immunosuppressive drugs such as cyclosporin A.