NFAT (nuclear factor of activated T cell transcription factors play critical roles in gene transcription during immune responses. The NFAT complex is made up of NFATc (NFATc1-4) protein and activator protein-1 (AP-1) transcription factor. NFAT proteins are regulated by Ca2+. NFATc1 is a substrate protein phosphatase calcineurin, a critical mediator of calcium signals during T-cell activation. NFATc1 activation requires the translocation of the transcription factor into the nucleus, a process that is mediated by calcineurin.