T time for ADAR: ADAR1 is required for T cell self-tolerance.

ADAR1, an RNA-editing enzyme, plays a key role in preventing self-RNAs from triggering autoinflammatory responses. In this issue of EMBO reports, Nakahama and colleagues uncover a novel role for ADAR1 in T cells . The authors report that in T cells, ADAR1-mediated suppression of type I interferon-stimulated gene (ISG) expression is required for thymic T cell self-tolerance and prevention of colitis. These findings establish a novel function of ADAR1 in T cells and suggest that autoreactive T cells may contribute to disease symptoms in autoinflammatory disorders.