This Pillars of Immunology article is a commentary on three pivotal articles: “Nuclear factor of activated T cells contains Fos and Jun,” an article written by J. Jain, P. G. McCaffrey, V. E. Valge-Archer, and A. Rao, and published in Nature, in 1992, https://www.nature.com/articles/356801a0; “The T-cell transcription factor NFATp is a substrate for calcineurin and interacts with Fos and Jun,” written by J. Jain, P. G. McCaffrey, Z. Miner, T. K. Kerppola, J. N. Lambert, G. L. Verdine, T. Curran, and A. Rao, and published in Nature, in 1993, https://www.nature.com/articles/365352a0; and “Isolation of the cyclosporin-sensitive T cell transcription factor NFATp,” written by P. G. McCaffrey, C. Luo, T. K. Kerppola, J. Jain, T. M. Badalian, A. M. Ho, E. Burgeon, W. S. Lane, J. N. Lambert, T. Curran, et al., and published in Science, in 1993, https://www.science.org/doi/10.1126/science.8235597.