Studying systemic lupus erythematosus (SLE), Kato and Perl showed that IL-21, identified as a key proinflamamtory cytokine in this disease, stimulated both TORC-1 and−2, and abrogated differentiation as well as function of Tregs along with autophagy, a phenomenon underlying Treg dysfunction in SLE (99). Here, CRTC1 is linked to systemic lupus erythematosus.